Publications by category
Books
Hunt J, Hosken DJ (eds)(2014). Genotype-by-Environment Interactions and Sexual Selection. , Wiley Blackwell.
Hosken DJ, Hunt J (2014). Preface.
Birkhead TR, Hosken, D.J. Pitnick, S. (2009). Sperm Biology: an Evolutionary Perspective. , Elsevier.
Journal articles
Singh KS, Hosken DJ, Wedell N, ffrench-Constant R, Bass C, Baxter S, Paszkiewicz K, Sharma MD (In Press). <i>De novo</i> genome assembly of the meadow brown butterfly, <i>Maniola jurtina</i>.
Abstract:
De novo genome assembly of the meadow brown butterfly, Maniola jurtina
AbstractBackgroundMeadow brown butterflies (Maniola jurtina) on the Isles of Scilly represent an ideal model in which to dissect the links between genotype, phenotype and long-term patterns of selection in the wild - a largely unfulfilled but fundamental aim of modern biology. To meet this aim, a clear description of genotype is required.FindingsHere we present the draft genome sequence of M. jurtina to serve as an initial genetic resource for this species. Seven libraries were constructed using DNA from multiple wild caught females and sequenced using Illumina, PacBio RSII and MinION technology. A novel hybrid assembly approach was employed to generate a final assembly with an N50 of 214 kb (longest scaffold 2.9 Mb). The genome encodes a total of 36,294 genes. 90.3% and 88.7% of core BUSCO (Benchmarking Universal Single-Copy Orthologs) Arthropoda and Insecta gene sets were recovered as complete single-copies from this assembly. Comparisons with 17 other Lepidopteran species placed 86.5% of the assembled genes in orthogroups.ConclusionsOur results provide the first high-quality draft genome and annotation of the butterfly M. jurtina.
Abstract.
Archer R, Recker M, Duffy E, Hosken D (In Press). Intralocus sexual conflict can resolve the male-female health-survival paradox. Nature Communications
Hosken DJ, Alonzo SH, Wedell N (In Press). Why aren’t females ornamented more often?.
Carey MR, Archer CR, Rapkin J, Castledine M, Jensen K, House CM, Hosken DJ, Hunt J (2022). Mapping sex differences in the effects of protein and carbohydrates on lifespan and reproduction in Drosophila melanogaster: is measuring nutrient intake essential?.
Biogerontology,
23(1), 129-144.
Abstract:
Mapping sex differences in the effects of protein and carbohydrates on lifespan and reproduction in Drosophila melanogaster: is measuring nutrient intake essential?
Understanding how diet affects reproduction and survival is a central aim in evolutionary biology. Although this relationship is likely to differ between the sexes, we lack data relating diet to male reproductive traits. One exception to this general pattern is Drosophila melanogaster, where male dietary intake was quantified using the CApillary FEeder (CAFE) method. However, CAFE feeding reduces D. melanogaster survival and reproduction, so may distort diet-fitness outcomes. Here, we use the Geometric Framework of Nutrition to create nutrient landscapes that map sex-specific relationships between protein, carbohydrate, lifespan and reproduction in D. melanogaster. Rather than creating landscapes with consumption data, we map traits onto the nutrient composition of forty agar-based diets, generating broad coverage of nutrient space. We find that male and female lifespan was maximised on low protein, high carbohydrate blends (~ 1P:15.9C). This nutrient ratio also maximised male reproductive rates, but females required more protein to maximise daily fecundity (1P:1.22C). These results are consistent with CAFE assay outcomes. However, the approach employed here improved female fitness relative to CAFE assays, while effects of agar versus CAFE feeding on male fitness traits depended on the nutrient composition of experimental diets. We suggest that informative nutrient landscapes can be made without measuring individual nutrient intake and that in many cases, this may be preferable to using the CAFE approach. The most appropriate method will depend on the question and species being studied, but the approach adopted here has the advantage of creating nutritional landscapes when dietary intake is hard to quantify.
Abstract.
Author URL.
Laugen AT, Hosken DJ, Reinhold K, Schwarzenbach GA, Hoeck PEA, Bussière LF, Blanckenhorn WU, Lüpold S (2022). Sperm competition in yellow dung flies: No consistent effect of sperm size. Journal of Evolutionary Biology, 35(10), 1309-1318.
Lymbery SJ, Tomkins JL, Buzatto BA, Hosken DJ (2021). Kin-mediated plasticity in alternative reproductive tactics.
Proceedings of the Royal Society B: Biological Sciences,
288(1956), 20211069-20211069.
Abstract:
Kin-mediated plasticity in alternative reproductive tactics
Conditional strategies occur when the relative fitness pay-off from expressing a given phenotype is contingent upon environmental circumstances. This conditional strategy model underlies cases of alternative reproductive tactics, in which individuals of one sex employ different means to obtain reproduction. How kin structure affects the expression of alternative reproductive tactics remains unexplored. We address this using the miteRhizoglyphus echinopus, in which large males develop into aggressive ‘fighters’ and small males develop into non-aggressive ‘scramblers.’ Because only fighters kill their rivals, they should incur a greater indirect fitness cost when competing with their relatives, and thus fighter expression could be reduced in the presence of relatives. We raised mites in full-sibling or mixed-sibship groups and found that fighters were more common at higher body weights in full-sibling groups, not less common as we predicted (small individuals were almost exclusively scramblers in both treatments). This result could be explained if relatedness and cue variability are interpreted signals of population density, since fighters are more common at low densities in this species. Alternatively, our results may indicate that males compete more intensely with relatives in this species. We provide the first evidence of kin-mediated plasticity in the expression of alternative reproductive tactics.
Abstract.
Okada K, Katsuki M, Sharma MD, Kiyose K, Seko T, Okada Y, Wilson AJ, Hosken DJ (2021). Natural selection increases female fitness by reversing the exaggeration of a male sexually selected trait.
Nature Communications,
12(1).
Abstract:
Natural selection increases female fitness by reversing the exaggeration of a male sexually selected trait
AbstractTheory shows how sexual selection can exaggerate male traits beyond naturally selected optima and also how natural selection can ultimately halt trait elaboration. Empirical evidence supports this theory, but to our knowledge, there have been no experimental evolution studies directly testing this logic, and little examination of possible associated effects on female fitness. Here we use experimental evolution of replicate populations of broad-horned flour beetles to test for effects of sex-specific predation on an exaggerated sexually selected male trait (the mandibles), while also testing for effects on female lifetime reproductive success. We find that populations subjected to male-specific predation evolve smaller sexually selected mandibles and this indirectly increases female fitness, seemingly through intersexual genetic correlations we document. Predation solely on females has no effects. Our findings support fundamental theory, but also reveal unforseen outcomes—the indirect effect on females—when natural selection targets sex-limited sexually selected characters.
Abstract.
Richardson S, Lintott P, Hosken D, Economou T, Matthews F (2021). Peaks in bat activity at turbines and the implications for mitigating the impact of wind energy developments on bats. Scientific Reports, 11
House CM, Lewis Z, Sharma MD, Hodgson DJ, Hunt J, Wedell N, Hosken DJ (2021). Sexual selection on the genital lobes of male Drosophila simulans.
Evolution,
75(2), 501-514.
Abstract:
Sexual selection on the genital lobes of male Drosophila simulans.
Sexual selection is thought to be responsible for the rapid divergent evolution of male genitalia with several studies detecting multivariate sexual selection on genital form. However, in most cases, selection is only estimated during a single episode of selection, which provides an incomplete view of net selection on genital traits. Here, we estimate the strength and form of multivariate selection on the genitalia arch of Drosophila simulans when mating occurs in the absence of a competitor and during sperm competition, in both sperm defence and offense roles (i.e. when mating first and last). We found that the strength of sexual selection on the genital arch was strongest during noncompetitive mating and weakest during sperm offense. However, the direction of selection was similar across selection episodes with no evidence for antagonistic selection. Overall, selection was not particularly strong despite genitals clearly evolving rapidly in this species.
Abstract.
Author URL.
Singh KS, Hosken DJ, Wedell N, Ffrench-Constant R, Bass C, Baxter S, Paszkiewicz K, Sharma MD (2020). De Novo Genome Assembly of the Meadow Brown Butterfly, Maniola jurtina.
G3 (Bethesda),
10(5), 1477-1484.
Abstract:
De Novo Genome Assembly of the Meadow Brown Butterfly, Maniola jurtina.
Meadow brown butterflies (Maniola jurtina) on the Isles of Scilly represent an ideal model in which to dissect the links between genotype, phenotype and long-term patterns of selection in the wild - a largely unfulfilled but fundamental aim of modern biology. To meet this aim, a clear description of genotype is required. Here we present the draft genome sequence of M. jurtina to serve as a founding genetic resource for this species. Seven libraries were constructed using pooled DNA from five wild caught spotted females and sequenced using Illumina, PacBio RSII and MinION technology. A novel hybrid assembly approach was employed to generate a final assembly with an N50 of 214 kb (longest scaffold 2.9 Mb). The sequence assembly described here predicts a gene count of 36,294 and includes variants and gene duplicates from five genotypes. Core BUSCO (Benchmarking Universal Single-Copy Orthologs) gene sets of Arthropoda and Insecta recovered 90.5% and 88.7% complete and single-copy genes respectively. Comparisons with 17 other Lepidopteran species placed 86.5% of the assembled genes in orthogroups. Our results provide the first high-quality draft genome and annotation of the butterfly M. jurtina.
Abstract.
Author URL.
Simmons LW, Parker GA, Hosken DJ (2020). Evolutionary insight from a humble fly: Sperm competition and the yellow dungfly.
Philosophical Transactions of the Royal Society B: Biological Sciences,
375(1813).
Abstract:
Evolutionary insight from a humble fly: Sperm competition and the yellow dungfly
Studies of the yellow dungfly in the 1960s provided one of the first quantitative demonstrations of the costs and benefits associated with male and female reproductive behaviour. These studies advanced appreciation of sexual selection as a significant evolutionary mechanism and contributed to the 1970s paradigm shift toward individual selectionist thinking. Three behaviours in particular led to the realization that sexual selection can continue during and after mating: (i) female receptivity to remating, (ii) sperm displacement and (iii) post-copulatory mate guarding. These behaviours either generate, or are adaptations to sperm competition, cryptic female choice and sexual conflict. Here we review this body of work, and its contribution to the development of post-copulatory sexual selection theory. This article is part of the theme issue 'Fifty years of sperm competition'.
Abstract.
Matsumura K, Abe MS, Sharma MD, Hosken DJ, Yoshii T, Miyatake T (2020). Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae).
Biological Journal of the Linnean Society,
130(1), 34-40.
Abstract:
Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae)
Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effects are rarely investigated. Here, we used 18 isofemale lines (genotypes) of Gnatocerus cornutus to assess rhythms of locomotor activity, while also testing for temperature effects. We found that total activity and the power of the circadian rhythm were affected by interactions between sex and genotype or between sex, genotype and temperature. The males tended to be more active and showed greater increases in activity, but this effect varied across both genotypes and temperatures. The period of activity varied only by genotype and was thus independent of temperature. The complicated genotype-sex-environment interactions we recorded stress the importance of investigating circadian activity in more integrated ways.
Abstract.
Theobald E, Hosken DJ, Foster P, Moyes K (2020). Mines and bats: the impact of open-pit mining on bat activity.
ACTA CHIROPTEROLOGICA,
22(1), 157-166.
Author URL.
Archer CR, Carey MR, Noda T, Store SJ, Hosken DJ (2020). Offspring sex ratios are stable across the life course in Drosophila simulans.
J Evol Biol,
33(11), 1606-1613.
Abstract:
Offspring sex ratios are stable across the life course in Drosophila simulans.
Within populations, adult sex ratios influence population growth and extinction risk, mating behaviours and parental care. Sex ratio adjustment can also have pronounced effects on individual fitness. Accordingly, it is important that we understand how often, and why, offspring sex ratios deviate from parity. In Drosophila melanogaster, females appear to improve their fitness by producing fewer sons when paired with older males. However, facultative sex ratio adjustment in D. melanogaster is controversial, and our understanding of how sex ratio skew affects fitness is hampered by pronounced sexual conflict in this species. Additionally, it is unclear whether maternal age or quality interacts with paternal age to influence offspring sex ratios. Here, we test whether offspring sex ratios vary as a function of maternal quality, and maternal and paternal age in Drosophila simulans, a sister species of D. melanogaster that lacks overt sexual conflict. We find that offspring sex ratios are slightly male-biased overall, but constant across the female life course, and independent of female quality, or paternal age. To really understand if, how and when females skew offspring sex ratios, we need studies linking offspring sex ratios to paternal and maternal phenotypes that are predicted to shift optimal investment in sons and daughters.
Abstract.
Author URL.
Richardson SM, Lintott PR, Hosken DJ, Mathews F (2019). An evidence-based approach to specifying survey effort in ecological assessments of bat activity.
Biological Conservation,
231, 98-102.
Abstract:
An evidence-based approach to specifying survey effort in ecological assessments of bat activity
Robust ecological assessments are fundamental for effective wildlife conservation. Owing to the high legal protection of bats, surveys are frequently required as part of ecological assessments. Yet there is uncertainty about the amount of survey effort that should be deployed to facilitate bat protection. Bat activity can be extremely variable, and capturing periods of high activity can be as important as estimating parameters such as the median activity level. However the frequency and intensity of surveys required to capture the required information is unknown. Here we assessed the probability that acoustic surveys of differing durations would detect periods of high activity within a focal site and the importance of a site relative to others in a regional or national context. We randomly subsampled from 660 nights of activity data collected from 33 wind farm sites across Britain. The minimum surveying effort required to classify bat activity accurately varied between species and was dependent on weather conditions. We found that the survey periods required to give reasonable certainty in assessing risk exceeded those currently recommended in Europe. The approach of using bat activity accumulation curves, as described here, is transferrable to other situations where determining surveying effort and risk is necessary to ensure that ecological assessments provide a robust evidence base, whilst minimising the time and expense of surveys.
Abstract.
Matsumura K, Archer CR, Hosken DJ, Miyatake T (2019). Artificial selection on walking distance suggests a mobility-sperm competitiveness trade-off.
Behavioral Ecology,
30(6), 1522-1529.
Abstract:
Artificial selection on walking distance suggests a mobility-sperm competitiveness trade-off
AbstractSecuring matings is a key determinant of fitness, and in many species, males are the sex that engages in mate searching. Searching for mates is often associated with increased mobility. This elevated investment in movement is predicted to trade-off with sperm competitiveness, but few studies have directly tested whether this trade-off occurs. Here, we assessed whether artificial selection on mobility affected sperm competitiveness and mating behavior, and if increased mobility was due to increased leg length in red flour beetles (Tribolium castaneum). We found that, in general, males selected for decreased mobility copulated for longer, stimulated females more during mating, and tended to be better sperm competitors. Surprisingly, they also had longer legs. However, how well males performed in sperm competition depended on females. Males with reduced mobility always copulated for longer than males with high mobility, but this only translated into greater fertilization success in females from control populations and not the selection populations (i.e. treatment females). These results are consistent with a mate-searching/mating-duration trade-off and broadly support a trade-off between mobility and sperm competitiveness.
Abstract.
Tourmente M, Archer CR, Hosken DJ (2019). Complex interactions between sperm viability and female fertility.
Sci Rep,
9(1).
Abstract:
Complex interactions between sperm viability and female fertility.
Sperm viability is a major male fitness component, with higher sperm viability associated with enhanced sperm competitiveness. While many studies have focussed on sperm viability from the male fitness standpoint, its impact on female fitness is less clear. Here we used a panel of 32 isogenic Drosophila simulans lines to test for genetic variation in sperm viability (percentage of viable cells). We then tested whether sperm viability affected female fitness by mating females to males from low or high sperm viability genotypes. We found significant variation in sperm viability among genotypes, and consistent with this, sperm viability was highly repeatable within genotypes. Additionally, females mated to high sperm viability males laid more eggs in the first seven hours after mating, and produced more offspring in total. However, the early increase in oviposition did not result in more offspring in the 8 hours following mating, suggesting that mating with high sperm-viability genotypes leads to egg wastage for females shortly after copulation. Although mating with high sperm-viability males resulted in higher female fitness in the long term, high quality ejaculates would result in a short-term female fitness penalty, or at least lower realised fitness, potentially generating sexual conflict over optimal sperm viability.
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Author URL.
Okada K, Okada Y, Dall SRX, Hosken DJ (2019). Loser-effect duration evolves independently of fighting ability. Proceedings of the Royal Society B: Biological Sciences, 286(1903), 20190582-20190582.
House CM, Rapkin J, Hunt J, Hosken DJ (2019). Operational sex ratio and density predict the potential for sexual selection in the broad-horned beetle.
Animal Behaviour,
152, 63-69.
Abstract:
Operational sex ratio and density predict the potential for sexual selection in the broad-horned beetle
Sexual selection can act on all aspects of the phenotype and the opportunity for selection (Is) sets its maximal strength. Popular approaches to alter is include the manipulation of the operational sex ratio (OSR) and/or density, with an increase in is predicted with a male-biased OSR and at higher density. However, debate continues regarding the utility of is to measure meaningful changes in the strength of selection, as changes in is with OSR and density may only reflect stochastic processes. Here we tested whether the manipulation of OSR and density alters is in the broad-horned flour beetle, Gnatocerus cornutus, a species where males are under intense sexual selection and the targets of selection are known. We also recorded the average number of fights and mating behaviour of individuals in our competitive arenas. We found significant main effects of OSR and density on is, with the opportunity for selection being highest in male-biased high-density treatments. There were also significant effects of OSR and density on the average number of matings, whereas only density influenced the average number of fights. These results suggest that manipulation of OSR and density influence the opportunity for sexual selection in G. cornutus and our observations of fighting and mating behaviour provide a proximate mechanism for the change in is.
Abstract.
Hosken DJ, Archer CR, Mank JE (2019). Sexual conflict.
Current Biology,
29(11), R451-R455.
Abstract:
Sexual conflict
Evolutionary conflict arises from differences in the fitness interests of replicating entities and has its roots in relatedness asymmetries. Every replicator is related to itself by 100%, but in most cases is less related to other replicators, which generates selfishness and conflicts of interest. Since this basic condition is the norm at many levels of biological organization, conflict is rife in biological systems. Sexual conflict, on which we focus here, is the evolutionary conflict that occurs between males and females because of their divergent fitness interests. Sexual conflict occurs despite sexual reproduction requiring some level of cooperation between males and females because the fitness interests of the sexes are nevertheless never perfectly aligned. In other words, males and females may agree on where they are going, but not necessarily on how to get there. Sexual conflict is a vast topic with relevance to many areas of biology and so here we restrict our focus to matters we think are of broadest interest. Hosken et al. introduce sexual conflict.
Abstract.
Hawkes MF, Duffy E, Joag R, Skeats A, Radwan J, Wedell N, Sharma MD, Hosken DJ, Troscianko J (2019). Sexual selection drives the evolution of male wing interference patterns.
Proc Biol Sci,
286(1903).
Abstract:
Sexual selection drives the evolution of male wing interference patterns.
The seemingly transparent wings of many insects have recently been found to display unexpected structural coloration. These structural colours (wing interference patterns: WIPs) may be involved in species recognition and mate choice, yet little is known about the evolutionary processes that shape them. Furthermore, to date investigations of WIPs have not fully considered how they are actually perceived by the viewers' colour vision. Here, we use multispectral digital imaging and a model of Drosophila vision to compare WIPs of male and female Drosophila simulans from replicate populations forced to evolve with or without sexual selection for 68 generations. We show that WIPs modelled in Drosophila vision evolve in response to sexual selection and provide evidence that WIPs correlate with male sexual attractiveness. These findings add a new element to the otherwise well-described Drosophila courtship display and confirm that wing colours evolve through sexual selection.
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Author URL.
Hosken DJ, Wilson A (2019). The problem of measuring trait-preference correlations without disrupting them. Behavioral Ecology, 30(6), 1518-1521.
Duffy E, Archer CR, Sharma MD, Prus M, Joag RA, Radwan J, Wedell N, Hosken DJ (2019). Wolbachia infection can bias estimates of intralocus sexual conflict.
Ecology and Evolution,
9(1), 328-338.
Abstract:
Wolbachia infection can bias estimates of intralocus sexual conflict
Males and females share most of their genome and develop many of the same traits. However, each sex frequently has different optimal values for these shared traits, creating intralocus sexual conflict. This conflict has been observed in wild and laboratory populations of insects and affects important evolutionary processes such as sexual selection, the maintenance of genetic variation, and possibly even speciation. Given the broad impacts of intralocus conflict, accurately detecting and measuring it is important. A common way to detect intralocus sexual conflict is to calculate the intersexual genetic correlation for fitness, with negative values suggesting conflict. Here, we highlight a potential confounder of this measure—cytoplasmic incompatibility caused by the intracellular parasite Wolbachia. Infection with Wolbachia can generate negative intersexual genetic correlations for fitness in insects, suggestive of intralocus sexual conflict. This is because cytoplasmic incompatibility reduces the fitness of uninfected females mated to infected males, while uninfected males will not suffer reductions in fitness if they mate with infected females and may even be fitter than infected males. This can lead to strong negative intersexual genetic correlations for fitness, mimicking intralocus conflict. We illustrate this issue using simulations and then present Drosophila simulans data that show how reproductive incompatibilities caused by Wolbachia infection can generate signals of intralocus sexual conflict. Given that Wolbachia infection in insect populations is pervasive, but populations usually contain both infected and uninfected individuals providing scope for cytoplasmic incompatibility, this is an important consideration for sexual conflict research but one which, to date, has been largely underappreciated.
Abstract.
Hosken DJ, Hodgson D, Buss D (2018). Beware the F-test (or, how to compare variances). Animal Behaviour, 136, 119-126.
Hosken DJ, Archer R, House C, Wedell N (2018). Penis evolution across species: divergence and diversity. Nature Reviews Urology
Hosken DJ, Sutter A, Barton S, Dev M, Basellini U, Archer R (2018). Senescent declines in elite tennis players are similar across the sexes. Behavioral Ecology
Maraqa MS, Griffin R, Sharma MD, Wilson AJ, Hunt J, Hosken DJ, House CM (2017). Constrained evolution of the sex comb in Drosophila simulans.
J Evol Biol,
30(2), 388-400.
Abstract:
Constrained evolution of the sex comb in Drosophila simulans.
Male fitness is dependent on sexual traits that influence mate acquisition (precopulatory sexual selection) and paternity (post-copulatory sexual selection), and although many studies have documented the form of selection in one or the other of these arenas, fewer have done it for both. Nonetheless, it appears that the dominant form of sexual selection is directional, although theoretically, populations should converge on peaks in the fitness surface, where selection is stabilizing. Many factors, however, can prevent populations from reaching adaptive peaks. Genetic constraints can be important if they prevent the development of highest fitness phenotypes, as can the direction of selection if it reverses across episodes of selection. In this study, we examine the evidence that these processes influence the evolution of the multivariate sex comb morphology of male Drosophila simulans. To do this, we conduct a quantitative genetic study together with a multivariate selection analysis to infer how the genetic architecture and selection interact. We find abundant genetic variance and covariance in elements of the sex comb. However, there was little evidence for directional selection in either arena. Significant nonlinear selection was detected prior to copulation when males were mated to nonvirgin females, and post-copulation during sperm offence (again with males mated to nonvirgins). Thus, contrary to our predictions, the evolution of the D. simulans sex comb is limited neither by genetic constraints nor by antagonistic selection between pre- and post-copulatory arenas, but nonlinear selection on the multivariate phenotype may prevent sex combs from evolving to reach some fitness maximizing optima.
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Author URL.
Baxter SW, Hoffman JI, Tregenza T, Wedell N, Hosken DJ (2017). EB Ford revisited: assessing the long-term stability of wing-spot patterns and population genetic structure of the meadow brown butterfly on the Isles of Scilly.
Heredity (Edinb),
118(4), 322-329.
Abstract:
EB Ford revisited: assessing the long-term stability of wing-spot patterns and population genetic structure of the meadow brown butterfly on the Isles of Scilly.
Understanding selection in the wild remains a major aim of evolutionary ecology and work by Ford and colleagues on the meadow brown butterfly Maniola jurtina did much to ignite this agenda. A great deal of their work was conducted during the 1950s on the Isles of Scilly. They documented island-specific wing-spot patterns that remained consistent over about a decade, but patterns on some islands changed after environmental perturbation. It was suggested that these wing-spot patterns reflected island-specific selection and that there was little migration between islands. However, genetic studies to test the underlying assumption of restricted migration are lacking and it is also unknown whether the originally described wing-spot patterns have persisted over time. We therefore collected female butterflies from five of Ford's original study locations, including three large islands (St Mary's, St Martin's and Tresco) and two small islands (Tean and St Helen's). Wing-spot patterns had not changed appreciably over time on three of the islands (two large and one small), but were significantly different on the other two. Furthermore, analysis of 176 amplified fragment length polymorphisms revealed significant genome-wide differentiation among the five islands. Our findings are consistent with Ford's conclusions that despite the close proximity of these islands, there is restricted gene flow among them.
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Author URL.
Wedell N, Rostant W, Bowyer J, Coupland J, Facey J, Hosken DJ (2017). Pleiotropic effects of DDT resistance on male size and behaviour. Behavior Genetics, 47, 449-458.
Archer CR, Stephens RM, Sharma MD, Hosken DJ (2017). The Drosophila simulans Y chromosome interacts with the autosomes to influence male fitness.
J Evol Biol,
30(10), 1821-1825.
Abstract:
The Drosophila simulans Y chromosome interacts with the autosomes to influence male fitness.
The Y chromosome should degenerate because it cannot recombine. However, male-limited transmission increases selection efficiency for male-benefit alleles on the Y, and therefore, Y chromosomes should contribute significantly to variation in male fitness. This means that although the Drosophila Y chromosome is small and gene-poor, Y-linked genes are vital for male fertility in Drosophila melanogaster and the Y chromosome has large male fitness effects. It is unclear whether the same pattern is seen in the closely related Drosophila simulans. We backcrossed Y chromosomes from three geographic locations into five genetic backgrounds and found strong Y and genetic background effects on male fertility. There was a significant Y-background interaction, indicating substantial epistasis between the Y and autosomal genes affecting male fertility. This supports accumulating evidence that interactions between the Y chromosome and the autosomes are key determinants of male fitness.
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Author URL.
Wedell N, Hosken DJ (2017). Three billion years of research
and development. NATURE ECOLOGY & EVOLUTION, 1
Lintott PR, Richardson SM, Hosken DJ, Fensome SA, Mathews F (2016). Ecological impact assessments fail to reduce risk of bat casualties at wind farms.
Curr Biol,
26(21), R1135-R1136.
Abstract:
Ecological impact assessments fail to reduce risk of bat casualties at wind farms.
Demand for renewable energy is rising exponentially. While this has benefits in reducing greenhouse gas emissions, there may be costs to biodiversity [1]. Environmental Impact Assessments (EIAs) are the main tool used across the world to predict the overall positive and negative effects of renewable energy developments before planning consent is given, and the Ecological Impact Assessments (EcIAs) within them assess their species-specific effects. Given that EIAs are undertaken globally, are extremely expensive, and are enshrined in legislation, their place in evidence-based decision making deserves evaluation. Here we assess how well EIAs of wind-farm developments protect bats. We found they do not predict the risks to bats accurately, and even in those cases where high risk was correctly identified, the mitigation deployed did not avert the risk. Given that the primary purpose of an EIA is to make planning decisions evidence-based, our results indicate that EIA mitigation strategies used to date have been ineffective in protecting bats. In the future, greater emphasis should be placed on assessing the actual impacts post-construction and on developing effective mitigation strategies.
Abstract.
Author URL.
Archer CR, Hosken DJ (2016). Evolution: Escaping the Inevitability of Ageing.
Current Biology,
26(5), R202-R204.
Abstract:
Evolution: Escaping the Inevitability of Ageing
William Hamilton argued that even species inhabiting the farthest flung corners of the universe should age. However, a recent study shows that to find a species that escapes ageing, you only need to look as far as your local pond.
Abstract.
Perry JC, Joag R, Hosken DJ, Wedell N, Radwan J, Wigby S (2016). Experimental evolution under hyper-promiscuity in Drosophila melanogaster.
BMC Evol Biol,
16(1).
Abstract:
Experimental evolution under hyper-promiscuity in Drosophila melanogaster.
BACKGROUND: the number of partners that individuals mate with over their lifetime is a defining feature of mating systems, and variation in mate number is thought to be a major driver of sexual evolution. Although previous research has investigated the evolutionary consequences of reductions in the number of mates, we know little about the costs and benefits of increased numbers of mates. Here, we use a genetic manipulation of mating frequency in Drosophila melanogaster to create a novel, highly promiscuous mating system. We generated D. melanogaster populations in which flies were deficient for the sex peptide receptor (SPR) gene - resulting in SPR- females that mated more frequently - and genetically-matched control populations, and allowed them to evolve for 55 generations. At several time-points during this experimental evolution, we assayed behavioural, morphological and transcriptional reproductive phenotypes expected to evolve in response to increased population mating frequencies. RESULTS: We found that males from the high mating frequency SPR- populations evolved decreased ability to inhibit the receptivity of their mates and decreased copulation duration, in line with predictions of decreased per-mating investment with increased sperm competition. Unexpectedly, SPR- population males also evolved weakly increased sex peptide (SP) gene expression. Males from SPR- populations initially (i.e. before experimental evolution) exhibited more frequent courtship and faster time until mating relative to controls, but over evolutionary time these differences diminished or reversed. CONCLUSIONS: in response to experimentally increased mating frequency, SPR- males evolved behavioural responses consistent with decreased male post-copulatory investment at each mating and decreased overall pre-copulatory performance. The trend towards increased SP gene expression might plausibly relate to functional differences in the two domains of the SP protein. Our study highlights the utility of genetic manipulations of animal social and sexual environments coupled with experimental evolution.
Abstract.
Author URL.
Sharma MD, Wilson AJ, Hosken DJ (2016). Fisher's sons' effect in sexual selection: absent, intermittent or just low experimental power?.
J Evol Biol,
29(12), 2464-2470.
Abstract:
Fisher's sons' effect in sexual selection: absent, intermittent or just low experimental power?
The Fisherian sexual selection paradigm has been called the null model of sexual selection. At its heart is the expectation of a genetic correlation (rG ) between female preference and male trait. However, recent meta-analysis has shown estimated correlations are often extremely weak and not statistically significant. We show here that systematic failure of studies to reject the null hypothesis that rG = 0 is almost certainly due to the low power of most experimental designs used. We provide an easy way to assess experimental power a priori and suggest that current data make it difficult to definitively test a key component of the Fisher effect.
Abstract.
Author URL.
Hawkes MF, Gamble CE, Turner ECR, Carey MR, Wedell N, Hosken DJ (2016). Intralocus sexual conflict and insecticide resistance.
Proceedings of the Royal Society B: Biological Sciences,
283(1843).
Abstract:
Intralocus sexual conflict and insecticide resistance
The BA allele of the Drosophila cytochrome P450 gene Cyp6g1 confers resistance to a range of insecticides. It is also subject to intralocus sexual conflict when introgressed into the Canton-S background, whose collection predates the widespread use of insecticides. In this genetic background, the allele confers a pleiotropic fitness benefit to females but a cost to males, and exhibits little sexual dimorphism in conferred insecticide resistance. It is unclear whether these sexually antagonistic effects also exist in current populations that have naturally evolved with insecticides, where genetic modifiers that offset male costs might be expected to evolve. Here, we explore these issues using Drosophila melanogaster caught recently from an Australian population in which the BA allele naturally segregates. While we find increased fecundity in insecticide-resistant BA females and no consistent evidence of fitness costs in males, experimental evolution indicates balancing selection at the locus. We suggest that this apparent discrepancy may be due to reduced investment in reproduction in resistant males. Our results at the population level are consistent with previous work, and suggest that individual-level fitness assays do not always capture sexually antagonistic fitness effects that emerge in a population context.
Abstract.
House CM, Jensen K, Rapkin J, Lane S, Okada K, Hosken DJ, Hunt J (2016). Macronutrient balance mediates the growth of sexually selected weapons but not genitalia in male broad-horned beetles.
Functional Ecology,
30(5), 769-779.
Abstract:
Macronutrient balance mediates the growth of sexually selected weapons but not genitalia in male broad-horned beetles
Condition is defined as the pool of resources available to an individual that can be allocated to fitness-enhancing traits. Consequently, condition could influence developmental trade-offs if any occur. Although many studies have manipulated diet to demonstrate condition-dependent trait expression, few studies have determined the contribution of specific nutrients to condition or trade-offs. We used nutritional geometry to quantify the effects of dietary protein and carbohydrate content on larval performance and the development of adult morphology including body size as well as a primary and secondary sexually selected trait in male broad-horned beetles, Gnatocerus cornutus. We found that offspring survival, development rate and morphological traits were highly affected by dietary carbohydrate content and to a lesser extent by protein content and that all traits were maximized at a protein-to-carbohydrate ratio around 1:2. The absolute size of a secondary sexual character, the mandibles, had a heightened response to the increased availability and ratio of both macronutrients. Male genitalia, in contrast, were relatively insensitive to the increased availability of macronutrients. Overall, while nutrition influenced trait expression, the nutritional requirements of development rate and morphological traits were largely the same and resource acquisition seems to implement only weak trade-offs in this species. This finding contrasts with some resource constraint predictions, as beetles seem able to simultaneously meet the nutritional requirements of most traits.
Abstract.
Campbell AL, Levitan DR, Hosken DJ, Lewis C (2016). Ocean acidification changes the male fitness landscape.
Sci Rep,
6Abstract:
Ocean acidification changes the male fitness landscape.
Sperm competition is extremely common in many ecologically important marine taxa. Ocean acidification (OA) is driving rapid changes to the marine environments in which freely spawned sperm operate, yet the consequences of OA on sperm performance are poorly understood in the context of sperm competition. Here, we investigated the impacts of OA (+1000 μatm pCO2) on sperm competitiveness for the sea urchin Paracentrotus lividus. Males with faster sperm had greater competitive fertilisation success in both seawater conditions. Similarly, males with more motile sperm had greater sperm competitiveness, but only under current pCO2 levels. Under OA the strength of this association was significantly reduced and there were male sperm performance rank changes under OA, such that the best males in current conditions are not necessarily best under OA. Therefore OA will likely change the male fitness landscape, providing a mechanism by which environmental change alters the genetic landscape of marine species.
Abstract.
Author URL.
Archer CR, Hosken DJ (2016). Peacock flies.
Current Biology,
26(21), R1124-R1126.
Abstract:
Peacock flies
A quick guide on peacock flies, a species of insect where, unusually, both males and females perform dances apparently to attract mates.
Abstract.
House CM, Sharma MD, Okada K, Hosken DJ (2016). Pre and Post-copulatory Selection Favor Similar Genital Phenotypes in the Male Broad Horned Beetle.
Integr Comp Biol,
56(4), 682-693.
Abstract:
Pre and Post-copulatory Selection Favor Similar Genital Phenotypes in the Male Broad Horned Beetle.
Sexual selection can operate before and after copulation and the same or different trait(s) can be targeted during these episodes of selection. The direction and form of sexual selection imposed on characters prior to mating has been relatively well described, but the same is not true after copulation. In general, when male-male competition and female choice favor the same traits then there is the expectation of reinforcing selection on male sexual traits that improve competitiveness before and after copulation. However, when male-male competition overrides pre-copulatory choice then the opposite could be true. With respect to studies of selection on genitalia there is good evidence that male genital morphology influences mating and fertilization success. However, whether genital morphology affects reproductive success in more than one context (i.e. mating versus fertilization success) is largely unknown. Here we use multivariate analysis to estimate linear and nonlinear selection on male body size and genital morphology in the flour beetle Gnatocerus cornutus, simulated in a non-competitive (i.e. monogamous) setting. This analysis estimates the form of selection on multiple traits and typically, linear (directional) selection is easiest to detect, while nonlinear selection is more complex and can be stabilizing, disruptive, or correlational. We find that mating generates stabilizing selection on male body size and genitalia, and fertilization causes a blend of directional and stabilizing selection. Differences in the form of selection across these bouts of selection result from a significant alteration of nonlinear selection on body size and a marginally significant difference in nonlinear selection on a component of genital shape. This suggests that both bouts of selection favor similar genital phenotypes, whereas the strong stabilizing selection imposed on male body size during mate acquisition is weak during fertilization.
Abstract.
Author URL.
Hosken DJ, Alonzo SH, Wedell N (2016). Why aren’t signals of female quality more common?. Animal Behaviour, 114, 199-201.
Brown AR, Owen SF, Peters J, Zhang Y, Soffker M, Paull GC, Hosken DJ, Wahab MA, Tyler CR (2015). Climate change and pollution speed declines in zebrafish populations.
Proc Natl Acad Sci U S A,
112(11), E1237-E1246.
Abstract:
Climate change and pollution speed declines in zebrafish populations.
Endocrine disrupting chemicals (EDCs) are potent environmental contaminants, and their effects on wildlife populations could be exacerbated by climate change, especially in species with environmental sex determination. Endangered species may be particularly at risk because inbreeding depression and stochastic fluctuations in male and female numbers are often observed in the small populations that typify these taxa. Here, we assessed the interactive effects of water temperature and EDC exposure on sexual development and population viability of inbred and outbred zebrafish (Danio rerio). Water temperatures adopted were 28 °C (current ambient mean spawning temperature) and 33 °C (projected for the year 2100). The EDC selected was clotrimazole (at 2 μg/L and 10 μg/L), a widely used antifungal chemical that inhibits a key steroidogenic enzyme [cytochrome P450(CYP19) aromatase] required for estrogen synthesis in vertebrates. Elevated water temperature and clotrimazole exposure independently induced male-skewed sex ratios, and the effects of clotrimazole were greater at the higher temperature. Male sex ratio skews also occurred for the lower clotrimazole exposure concentration at the higher water temperature in inbred fish but not in outbred fish. Population viability analysis showed that population growth rates declined sharply in response to male skews and declines for inbred populations occurred at lower male skews than for outbred populations. These results indicate that elevated temperature associated with climate change can amplify the effects of EDCs and these effects are likely to be most acute in small, inbred populations exhibiting environmental sex determination and/or differentiation.
Abstract.
Author URL.
Okada K, Archer CR, Katsuki M, Suzaki Y, Sharma MD, House CM, Hosken DJ (2015). Polyandry and fitness in female horned flour beetles, Gnatocerus cornutus.
Animal Behaviour,
106, 11-16.
Abstract:
Polyandry and fitness in female horned flour beetles, Gnatocerus cornutus
Although polyandry is common, it is often unclear why females mate with multiple males, because although polyandry may provide females with direct or indirect fitness benefits, it can also be costly. Our understanding of polyandry is also restricted by the relative paucity of studies that disentangle the fitness effects of mating more than once with a single male and mating with multiple males. Here we investigated potential benefits and costs of polyandry in the horned beetle, Gnatocerus cornutus, while controlling for the number of matings. We found that female life span was independent of mating frequency, indicating that mating itself is not very costly. However, females that mated more than once laid more eggs and had greater lifetime reproductive success than singly mated females. Because the magnitude of these effects was similar in monandrous and polyandrous females, this improved fertility was due to multiple mating itself, rather than mating with multiple males. However, although polyandrous females produced more attractive sons, these males tended to have smaller mandibles and so may fare less well in male-male competition. The se results indicate that polyandry is relatively cost free, at least in the laboratory, and has direct and indirect benefits to female fitness. However, because the attractive sons produced by polyandrous females may fight less well, the indirect benefits of polyandry will depend on the intensity of male-male competition and how free females are to exert mate choice. Where competition between males is intense, polyandry benefits via son attractiveness may be reduced and perhaps even carry costs to female fitness.
Abstract.
Moussy C, Atterby H, Griffiths AGF, Allnutt TR, Mathews F, Smith GC, Aegerter JN, Bearhop S, Hosken DJ (2015). Population genetic structure of serotine bats (Eptesicus serotinus) across Europe and implications for the potential spread of bat rabies (European bat lyssavirus EBLV-1).
Heredity (Edinb),
115(1), 83-92.
Abstract:
Population genetic structure of serotine bats (Eptesicus serotinus) across Europe and implications for the potential spread of bat rabies (European bat lyssavirus EBLV-1).
Understanding of the movements of species at multiple scales is essential to appreciate patterns of population connectivity and in some cases, the potential for pathogen transmission. The serotine bat (Eptesicus serotinus) is a common and widely distributed species in Europe where it frequently harbours European bat lyssavirus type 1 (EBLV-1), a virus causing rabies and transmissible to humans. In the United Kingdom, it is rare, with a distribution restricted to south of the country and so far the virus has never been found there. We investigated the genetic structure and gene flow of E. serotinus across the England and continental Europe. Greater genetic structuring was found in England compared with continental Europe. Nuclear data suggest a single population on the continent, although further work with more intensive sampling is required to confirm this, while mitochondrial sequences indicate an east-west substructure. In contrast, three distinct populations were found in England using microsatellite markers, and mitochondrial diversity was very low. Evidence of nuclear admixture indicated strong male-mediated gene flow among populations. Differences in connectivity could contribute to the high viral prevalence on the continent in contrast with the United Kingdom. Although the English Channel was previously thought to restrict gene flow, our data indicate relatively frequent movement from the continent to England highlighting the potential for movement of EBLV-1 into the United Kingdom.
Abstract.
Author URL.
Hodgson D, McDonald JL, Hosken DJ (2015). Resilience is Complicated, but Comparable: a Reply to Yeung and Richardson. Trends in Ecology and Evolution
Archer CR, Duffy E, Hosken DJ, Mokkonen M, Okada K, Oku K, Sharma MD, Hunt J (2015). Sex-specific effects of natural and sexual selection on the evolution of life span and ageing in Drosophila simulans.
Functional Ecology,
29(4), 562-569.
Abstract:
Sex-specific effects of natural and sexual selection on the evolution of life span and ageing in Drosophila simulans
Variation in the strength of age-dependent natural selection shapes differences in ageing rates across species and populations. Likewise, sexual selection can promote divergent patterns of senescence across the sexes. However, the effects of these processes on the evolution of ageing have largely been considered independently, and interactions between them are poorly understood. We use experimental evolution to investigate how natural and sexual selection affect life span and ageing in Drosophila simulans. Replicate populations were evolved under lifetime monogamy (relaxed sexual selection) or lifetime polyandry (elevated sexual selection) and at one of two temperatures, 25 °C (relaxed natural selection) or 27 °C (enhanced natural selection), in a fully factorial design. We measured longevity in 150 individually housed flies taken from each of three replicate populations per selection regime. We found that natural and sexual selection affected the evolution of life span via sex-specific effects on different ageing parameters (ageing rate vs. baseline mortality): natural selection reduced the rate of ageing in both sexes but increased male baseline mortality, while sexual selection elevated baseline mortality in both sexes but particularly in males. This means that sexual and natural selection interacted to reduce male life span but acted on female life span by independently affecting particular ageing parameters. Sex-specific effects of sexual and natural selection may help explain the diverse patterns of ageing seen in nature but complicate predictions about how ageing and life span evolve across the sexes.
Abstract.
Rostant WG, Kay C, Wedell N, Hosken DJ (2015). Sexual conflict maintains variation at an insecticide resistance locus.
BMC Biol,
13Abstract:
Sexual conflict maintains variation at an insecticide resistance locus.
BACKGROUND: the maintenance of genetic variation through sexually antagonistic selection is controversial, partly because specific sexually-antagonistic alleles have not been identified. The Drosophila DDT resistance allele (DDT-R) is an exception. This allele increases female fitness, but simultaneously decreases male fitness, and it has been suggested that this sexual antagonism could explain why polymorphism was maintained at the locus prior to DDT use. We tested this possibility using a genetic model and then used evolving fly populations to test model predictions. RESULTS: Theory predicted that sexual antagonism is able to maintain genetic variation at this locus, hence explaining why DDT-R did not fix prior to DDT use despite increasing female fitness, and experimentally evolving fly populations verified theoretical predictions. CONCLUSIONS: This demonstrates that sexually antagonistic selection can maintain genetic variation and explains the DDT-R frequencies observed in nature.
Abstract.
Author URL.
Hodgson D, McDonald JL, Hosken DJ (2015). What do you mean, 'resilient'?.
Trends in Ecology and EvolutionAbstract:
What do you mean, 'resilient'?
In a world beset by environmental disasters and anthropogenic disturbances, resilience might be the key to the persistence of natural systems. Yet, the 'measurement' of resilience is hampered by the multiple (and often conflicting) processes that yield the response of systems to insult. We recommend the simultaneous consideration of 'resistance' and 'recovery' as measurable components that together represent resilience.
Abstract.
Mank JE, Hosken DJ, Wedell N (2014). Conflict on the sex chromosomes: cause, effect, and complexity.
Cold Spring Harb Perspect Biol,
6(12).
Abstract:
Conflict on the sex chromosomes: cause, effect, and complexity.
Intralocus sexual conflict and intragenomic conflict both affect sex chromosome evolution and can in extreme cases even cause the complete turnover of sex chromosomes. Additionally, established sex chromosomes often become the focus of heightened conflict. This creates a tangled relationship between sex chromosomes and conflict with respect to cause and effect. To further complicate matters, sexual and intragenomic conflict may exacerbate one another and thereby further fuel sex chromosome change. Different magnitudes and foci of conflict offer potential explanations for lineage-specific variation in sex chromosome evolution and answer long-standing questions as to why some sex chromosomes are remarkably stable, whereas others show rapid rates of evolutionary change.
Abstract.
Author URL.
Ingleby FC, Hosken DJ, Flowers K, Hawkes MF, Lane SM, Rapkin J, House CM, Sharma MD, Hunt J (2014). Environmental heterogeneity, multivariate sexual selection and genetic constraints on cuticular hydrocarbons in Drosophila simulans.
Journal of Evolutionary Biology,
27(4), 700-713.
Abstract:
Environmental heterogeneity, multivariate sexual selection and genetic constraints on cuticular hydrocarbons in Drosophila simulans
Sexual selection is responsible for the evolution of many elaborate traits, but sexual trait evolution could be influenced by opposing natural selection as well as genetic constraints. As such, the evolution of sexual traits could depend heavily on the environment if trait expression and attractiveness vary between environments. Here, male Drosophila simulans were reared across a range of diets and temperatures, and we examined differences between these environments in terms of (i) the expression of male cuticular hydrocarbons (CHCs) and (ii) which male CHC profiles were most attractive to females. Temperature had a strong effect on male CHC expression, whereas the effect of diet was weaker. Male CHCs were subject to complex patterns of directional, quadratic and correlational sexual selection, and we found differences between environments in the combination of male CHCs that were most attractive to females, with clearer differences between diets than between temperatures. We also show that genetic covariance between environments is likely to cause a constraint on independent CHC evolution between environments. Our results demonstrate that even across the narrow range of environmental variation studied here, predicting the outcome of sexual selection can be extremely complicated, suggesting that studies ignoring multiple traits or environments may provide an over-simplified view of the evolution of sexual traits. © 2014 European Society for Evolutionary Biology.
Abstract.
Duffy E, Joag R, Radwan J, Wedell N, Hosken DJ (2014). Inbreeding alters intersexual fitness correlations in Drosophila simulans.
ECOLOGY AND EVOLUTION,
4(17), 3330-3338.
Author URL.
Edward DA, Stockley P, Hosken DJ (2014). Sexual conflict and sperm competition.
Cold Spring Harb Perspect Biol,
7(4).
Abstract:
Sexual conflict and sperm competition.
Traits that increase a male's fertilization success during sperm competition can be harmful to females and therefore represent a source of sexual conflict. In this review, we consider the variety of male adaptations to sperm competition (MASC) that may give rise to sexual conflict-including mate guarding, prolonged copulations, the transfer of large numbers of sperm, and the manipulation of females through nonsperm components of the ejaculate. We then reflect on the fitness economics influencing the escalation of these sexual conflicts, considering the likelihood of females evolving traits to offset the negative effects of MASC when compared with the strong selection on males that lead to MASC. We conclude by discussing the potential evolutionary outcomes of sexual conflict arising from MASC, including the opportunities for females to mitigate conflict costs and the prospects for conflict resolution.
Abstract.
Author URL.
Okada K, Katsuki M, Sharma MD, House CM, Hosken DJ (2014). Sexual conflict over mating in Gnatocerus cornutus? Females prefer lovers not fighters.
Proc Biol Sci,
281(1785).
Abstract:
Sexual conflict over mating in Gnatocerus cornutus? Females prefer lovers not fighters.
Female mate choice and male-male competition are the typical mechanisms of sexual selection. However, these two mechanisms do not always favour the same males. Furthermore, it has recently become clear that female choice can sometimes benefit males that reduce female fitness. So whether male-male competition and female choice favour the same or different males, and whether or not females benefit from mate choice, remain open questions. In the horned beetle, Gnatocerus cornutus, males have enlarged mandibles used to fight rivals, and larger mandibles provide a mating advantage when there is direct male-male competition for mates. However, it is not clear whether females prefer these highly competitive males. Here, we show that female choice targets male courtship rather than mandible size, and these two characters are not phenotypically or genetically correlated. Mating with attractive, highly courting males provided indirect benefits to females but only via the heritability of male attractiveness. However, mating with attractive males avoids the indirect costs to daughters that are generated by mating with competitive males. Our results suggest that male-male competition may constrain female mate choice, possibly reducing female fitness and generating sexual conflict over mating.
Abstract.
Author URL.
Hodgson DJ, Hosken DJ (2014). Ultimate and proximate functions of sperm RNA: a reply to Holman and Price.
Trends Ecol Evol,
29(12).
Author URL.
Hosken DJ, Hodgson DJ (2014). Why do sperm carry RNA? Relatedness, conflict, and control.
Trends Ecol Evol,
29(8), 451-455.
Abstract:
Why do sperm carry RNA? Relatedness, conflict, and control.
Classically, sperm were seen as transcriptionally inactive vehicles for delivering the paternal haplotype to an egg. Yet, it has become apparent that sperm also carry thousands of different RNAs, and the functions of most of these are unknown. Here, we make four novel suggestions for sperm RNA function. First, they could act as relatedness markers facilitating sperm cooperation. Second, they could act as paternally imposed suppressors of haploid interests. Third, they could act as a nuptial gift, providing the female with resources that entice her to fertilise ova using the sperm of the gift-provider. Fourth, they could represent the contents of a Trojan horse, delivered by males to manipulate female reproduction. We discuss these ideas and suggest how they might be tested.
Abstract.
Author URL.
Mathews F, Swindells M, Goodhead R, August TA, Hardman P, Linton DM, Hosken DJ (2013). EFFECTIVENESS OF SEARCH DOGS COMPARED WITH HUMAN OBSERVERS IN LOCATING BAT CARCASSES AT WIND TURBINE SITES: a BLINDED RANDOMIZED TRIAL. Wildlife Society Bulletin, 37, 34-40.
Ingleby FC, Hunt J, Hosken DJ (2013). Genotype-by-Environment Interactions for Female Mate Choice of Male Cuticular Hydrocarbons in Drosophila simulans.
PLoS ONE,
8(6).
Abstract:
Genotype-by-Environment Interactions for Female Mate Choice of Male Cuticular Hydrocarbons in Drosophila simulans
Recent research has highlighted the potential importance of environmental and genotype-by-environment (G×E) variation in sexual selection, but most studies have focussed on the expression of male sexual traits. Consequently, our understanding of genetic variation for plasticity in female mate choice is extremely poor. In this study we examine the genetics of female mate choice in Drosophila simulans using isolines reared across two post-eclosion temperatures. There was evidence for G×Es in female choosiness and preference, which suggests that the evolution of female mate choice behaviour could differ across environments. However, the ranked order of preferred males was consistent across females and environments, so the same males are favoured by mate choice in spite of G×Es. Our study highlights the importance of taking cross-environment perspectives in order to gain a more comprehensive understanding of the operation of sexual selection. © 2013 Ingleby et al.
Abstract.
Ingleby FC, Hosken DJ, Flowers K, Hawkes MF, Lane SM, Rapkin J, Dworkin I, Hunt J (2013). Genotype-by-environment interactions for cuticular hydrocarbon expression in Drosophila simulans.
J Evol Biol,
26(1), 94-107.
Abstract:
Genotype-by-environment interactions for cuticular hydrocarbon expression in Drosophila simulans.
Genotype-by-environment interactions (G × Es) describe genetic variation for phenotypic plasticity. Recent interest in the role of these interactions in sexual selection has identified G × Es across a diverse range of species and sexual traits. Additionally, theoretical work predicts that G × Es in sexual traits could help to maintain genetic variation, but could also disrupt the reliability of these traits as signals of mate quality. However, empirical tests of these theoretical predictions are scarce. We reared iso-female lines of Drosophila simulans across two axes of environmental variation (diet and temperature) in a fully factorial design and tested for G × Es in the expression of cuticular hydrocarbons (CHCs), a multivariate sexual trait in this species. We find sex-specific environmental, genetic and G × E effects on CHC expression, with G × Es for diet in both male and female CHC profile and a G × E for temperature in females. We also find some evidence for ecological crossover in these G × Es, and by quantifying variance components, genetic correlations and heritabilities, we show the potential for these G × Es to help maintain genetic variation and cause sexual signal unreliability in D. simulans CHC profiles.
Abstract.
Author URL.
Ingleby FC, Hunt J, Hosken DJ (2013). Heritability of male attractiveness persists despite evidence for unreliable sexual signals in Drosophila simulans.
Journal of Evolutionary Biology,
26(2), 311-324.
Abstract:
Heritability of male attractiveness persists despite evidence for unreliable sexual signals in Drosophila simulans
Sexual signals can be used to attract mates, but to be honest indicators of signaller quality they need to convey information reliably. However, environmental variation and genotype-by-environment (G × E) interactions have the potential to compromise the reliability of sexual signals. Here, we test the reliability of cuticular hydrocarbons (CHCs) as signals of heritable aspects of male attractiveness in Drosophila simulans. We examined the heritability of male attractiveness and a measure of the difference between fathers' and sons' CHC profiles across dietary and temperature environments. Our results show that environmental heterogeneity disrupts the similarity of some components of father and son CHC profile. However, overall male attractiveness is heritable within and across environments, so that sire attractiveness is a good predictor of son attractiveness even with environmental heterogeneity. This suggests that although some male CHC signals are unreliable, attractive genotypes retain their attractiveness across environments on average. © 2012 European Society for Evolutionary Biology.
Abstract.
Ala-Honkola O, Hosken DJ, Manier MK, Lüpold S, Droge-Young EM, Berben KS, Collins WF, Belote JM, Pitnick S (2013). Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster.
Ecol Evol,
3(7), 2089-2102.
Abstract:
Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster.
Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e. fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer the mode of past selection on them. The use of transgenic populations of Drosophila melanogaster with red or green fluorescent-tagged sperm heads permitted in vivo discrimination of sperm from competing males and quantification of characteristics of ejaculate composition, performance, and fate. We found that male attractiveness (mating latency) and competitive fertilization success (P2) both show some inbreeding depression, suggesting they may have been under directional selection, whereas sperm length showed no inbreeding depression suggesting a history of stabilizing selection. However, despite having measured several sperm quality and quantity traits, our data did not allow us to discern the mechanism underlying the lowered competitive fertilization success of inbred (f = 0.50) males.
Abstract.
Author URL.
Bickley LK, Brown AR, Hosken DJ, Hamilton PB, Le Page G, Paull GC, Owen SF, Tyler CR (2013). Interactive effects of inbreeding and endocrine disruption on reproduction in a model laboratory fish.
Evolutionary Applications,
6(2), 279-289.
Abstract:
Interactive effects of inbreeding and endocrine disruption on reproduction in a model laboratory fish
Inbreeding depression is expected to be more severe in stressful environments. However, the extent to which inbreeding affects the vulnerability of populations to environmental stressors, such as chemical exposure, remains unresolved. Here we report on the combined impacts of inbreeding and exposure to an endocrine disrupting chemical (the fungicide clotrimazole) on zebrafish (Danio rerio). We show that whilst inbreeding can negatively affect reproductive traits, not all traits are affected equally. Inbreeding depression frequently only became apparent when fish were additionally stressed by chemical exposure. Embryo viability was significantly reduced in inbred exposed fish and there was a tendency for inbred males to sire fewer offspring when in direct competition with outbred individuals. Levels of plasma 11-ketotestosterone, a key male sex hormone, showed substantial inbreeding depression that was unaffected by addition of the fungicide. In contrast, there was no effect of inbreeding or clotrimazole exposure on egg production. Overall, our data provide evidence that stress may amplify the effects of inbreeding on key reproductive traits, particularly those associated with male fitness. This may have important implications when considering the consequences of exposure to chemical pollutants on the fitness of wild populations. Journal compilation © 2013 Blackwell Publishing Ltd62 February 2013 10.1111/j.1752-4571.2012.00288.x Original Article Original Articles © 2012 Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution Non Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Abstract.
Moussy C, Hosken DJ, Mathews F, Smith GC, Aegerter JN, Bearhop S (2013). Migration and dispersal patterns of bats and their influence on genetic structure. Mammal Review, 43, 183-195.
Sharma MD, Minder AM, Hosken DJ (2013). No association between sperm competition and sperm length variation across dung flies (Scathophagidae).
J Evol Biol,
26(11), 2341-2349.
Abstract:
No association between sperm competition and sperm length variation across dung flies (Scathophagidae).
Sperm length is extremely variable across species, but a general explanation for this variation is lacking. However, when the risk of sperm competition is high, sperm length is predicted to be less variable within species, and there is some evidence for this in birds and social insects. Here, we examined intraspecific variation in sperm length, both within and between males, and its potential associations with sperm competition risk and variation in female reproductive tract morphology across dung flies. We used two measures of variation in sperm size, and testis size was employed as our index of sperm competition risk. We found no evidence of associations between sperm length variation and sperm competition or female reproductive tract variation. These results suggest that variation in sperm competition risk may not always be associated with variation in sperm morphology, and the cause(s) of sperm length variation in dung flies remains unclear.
Abstract.
Author URL.
Mank JE, Wedell N, Hosken DJ (2013). Polyandry and sex-specific gene expression.
Philosophical transactions of the Royal Society of London. Series B, Biological sciences,
368(1613).
Abstract:
Polyandry and sex-specific gene expression.
Polyandry is widespread in nature, and has important evolutionary consequences for the evolution of sexual dimorphism and sexual conflict. Although many of the phenotypic consequences of polyandry have been elucidated, our understanding of the impacts of polyandry and mating systems on the genome is in its infancy. Polyandry can intensify selection on sexual characters and generate more intense sexual conflict. This has consequences for sequence evolution, but also for sex-biased gene expression, which acts as a link between mating systems, sex-specific selection and the evolution of sexual dimorphism. We discuss this and the remarkable confluence of sexual-conflict theory and patterns of gene expression, while also making predictions about transcription patterns, mating systems and sexual conflict. Gene expression is a key link in the genotype-phenotype chain, and although in its early stages, understanding the sexual selection-transcription relationship will provide significant insights into this critical association.
Abstract.
House CM, Lewis Z, Hodgson DJ, Wedell N, Sharma MD, Hunt J, Hosken DJ (2013). Sexual and natural selection both influence male genital evolution.
PLoS One,
8(5).
Abstract:
Sexual and natural selection both influence male genital evolution.
Rapid and divergent evolution of male genital morphology is a conspicuous and general pattern across internally fertilizing animals. Rapid genital evolution is thought to be the result of sexual selection, and the role of natural selection in genital evolution remains controversial. However, natural and sexual selection are believed to act antagonistically on male genital form. We conducted an experimental evolution study to investigate the combined effects of natural and sexual selection on the genital-arch lobes of male Drosophila simulans. Replicate populations were forced to evolve under lifetime monogamy (relaxed sexual selection) or lifetime polyandry (elevated sexual selection) and two temperature regimes, 25°C (relaxed natural selection) or 27°C (elevated natural selection) in a fully factorial design. We found that natural and sexual selection plus their interaction caused genital evolution. Natural selection caused some aspects of genital form to evolve away from their sexually selected shape, whereas natural and sexual selection operated in the same direction for other shape components. Additionally, sexual and natural selection tended to favour larger genitals. Thus we find that the underlying selection driving genital evolution is complex, does not only involve sexual selection, and that natural selection and sexual selection do not always act antagonistically.
Abstract.
Author URL.
Sharma MD, Hunt J, Hosken DJ (2012). Antagonistic responses to natural and sexual selection and the sex-specific evolution of cuticular hydrocarbons in Drosophila simulans.
Evolution,
66(3), 665-677.
Abstract:
Antagonistic responses to natural and sexual selection and the sex-specific evolution of cuticular hydrocarbons in Drosophila simulans.
Natural and sexual selection are classically thought to oppose one another, and although there is evidence for this, direct experimental demonstrations of this antagonism are largely lacking. Here, we assessed the effects of sexual and natural selection on the evolution of cuticular hydrocarbons (CHCs), a character subject to both modes of selection, in Drosophila simulans. Natural selection and sexual selection were manipulated in a fully factorial design, and after 27 generations of experimental evolution, the responses of male and female CHCs were assessed. The effects of natural and sexual selection differed greatly across the sexes. The responses of female CHCs were generally small, but CHCs evolved predominantly in the direction of natural selection. For males, profiles evolved via sexual and natural selection, as well as through the interaction between the two, with some male CHC components only evolving in the direction of natural selection when sexual selection was relaxed. These results indicate sex-specific responses to selection, and that sexual and natural selection act antagonistically for at least some combinations of CHCs.
Abstract.
Author URL.
Price TA, Hosken DJ (2012). Evolution: why good dads win.
Curr Biol,
22(4), R135-R137.
Abstract:
Evolution: why good dads win.
Males usually do not provide parental care and with good reason, they may be caring for the offspring of someone else. But there are cases of male-only care even when certainty of paternity is low: why? a new model suggests female choice may provide the answer.
Abstract.
Author URL.
Katsuki M, Harano T, Miyatake T, Okada K, Hosken DJ (2012). Intralocus sexual conflict and offspring sex ratio.
Ecology Letters,
15(3), 193-197.
Abstract:
Intralocus sexual conflict and offspring sex ratio
Males and females frequently have different fitness optima for shared traits, and as a result, genotypes that are high fitness as males are low fitness as females, and vice versa. When this occurs, biasing of offspring sex-ratio to reduce the production of the lower-fitness sex would be advantageous, so that for example, broods produced by high-fitness females should contain fewer sons. We tested for offspring sex-ratio biasing consistent with these predictions in broad-horned flour beetles. We found that in both wild-type beetles and populations subject to artificial selection for high- and low-fitness males, offspring sex ratios were biased in the predicted direction: low-fitness females produced an excess of sons, whereas high-fitness females produced an excess of daughters. Thus, these beetles are able to adaptively bias sex ratio and recoup indirect fitness benefits of mate choice. © 2012 Blackwell Publishing Ltd/CNRS.
Abstract.
Katsuki M, Harano T, Miyatake T, Okada K, Hosken DJ (2012). Intralocus sexual conflict and offspring sex ratio.
Ecol Lett,
15(3), 193-197.
Abstract:
Intralocus sexual conflict and offspring sex ratio.
Males and females frequently have different fitness optima for shared traits, and as a result, genotypes that are high fitness as males are low fitness as females, and vice versa. When this occurs, biasing of offspring sex-ratio to reduce the production of the lower-fitness sex would be advantageous, so that for example, broods produced by high-fitness females should contain fewer sons. We tested for offspring sex-ratio biasing consistent with these predictions in broad-horned flour beetles. We found that in both wild-type beetles and populations subject to artificial selection for high- and low-fitness males, offspring sex ratios were biased in the predicted direction: low-fitness females produced an excess of sons, whereas high-fitness females produced an excess of daughters. Thus, these beetles are able to adaptively bias sex ratio and recoup indirect fitness benefits of mate choice.
Abstract.
Author URL.
Hosken DJ (2012). Rationality: Evidence must prevail.
Nature,
489(7417).
Author URL.
Sharma MD, Griffin RM, Hollis J, Tregenza T, Hosken DJ (2012). Reinvestigating good genes benefits of mate choice in Drosophila simulans.
Biological Journal of the Linnean Society,
106(2), 295-306.
Abstract:
Reinvestigating good genes benefits of mate choice in Drosophila simulans
Studies investigating the genetic benefits of female mate choice frequently find Fisherian benefits to choice, at the same time as detecting small or no good genes (viability) effects. This could be because sons trade-off viability for increased mating success and, accordingly, it has been suggested that good genes benefits should be investigated in daughters. However, good genes benefits via daughters could also be disrupted by intralocus sexual conflict. As a result, it is not clear when and if good genes benefits should accrue. We investigated potential good genes effects in Drosophila simulans using an isofemale line approach. We assessed the attractiveness of males in two different ways and then measured the longevity, as well as lifetime reproductive success, of their daughters. We also assessed potential direct benefits of female mate choice and good genes effects through the longevity of sons. We found no evidence of direct or good genes benefits to females mating with attractive males, and the failure to find good genes effects via daughters was apparently not a result of masking through intralocus sexual conflict. The results obtained in the present study are consistent with previous findings in this species, and suggest that good genes benefits are at best very small in our study population. © 2012 the Linnean Society of London.
Abstract.
Smith DT, Sirot LK, Wolfner MF, Hosken DJ, Wedell N (2012). The consequences of genetic variation in sex peptide expression levels for egg laying and retention in females.
Heredity,
109(4), 222-225.
Abstract:
The consequences of genetic variation in sex peptide expression levels for egg laying and retention in females
The accessory gland proteins (Acps) that male Drosophila melanogaster produce and transfer to females during copulation are key to male and female fitness. One Acp, the sex peptide (SP), is largely responsible for a dramatic increase in female egg laying and decrease in female receptivity after copulation. While genetic variation in male SP expression levels correlate with refractory period duration in females, it is unknown whether male SP expression influences female egg laying or if any effect of SP is mediated by SP retention in the female reproductive tract. Here we measured the amount of SP retained in the female reproductive tract after mating and female egg laying after copulating with virgin males. We found no correlation between male SP expression levels and egg laying, or the amount of SP in the female reproductive tract after mating. Additionally, the amount of SP retained in the female did not influence egg laying. These finding suggests that additional factors, such as variation in other Acps, are important for the retention of SP in females and its quantitative effects on egg laying. It also shows that egg laying and refractory period response to SP is at least partially uncoupled. © 2012 Macmillan Publishers Limited all rights reserved.
Abstract.
Sharma MD, Mitchell C, Hunt J, Tregenza T, Hosken DJ (2012). The genetics of cuticular hydrocarbon profiles in the fruit fly Drosophila simulans.
J Hered,
103(2), 230-239.
Abstract:
The genetics of cuticular hydrocarbon profiles in the fruit fly Drosophila simulans.
Female mate choice is one mechanism of sexual selection and, provided there is adequate genetic variation in the male traits that are the target of this selection, they will evolve via female choice. Cuticular hydrocarbons (CHCs) are important in Drosophila mate choice, but relatively little is known about the underlying genetic architecture of CHC profiles in Drosophila simulans. Here, we used gas chromatography-mass spectrometry to investigate patterns of genetic variation in the CHC profiles of male and female D. simulans using isofemale lines. We found substantial genetic variation for CHC profiles and individual CHC components, and individual CHCs were frequently strongly genetically correlated, with a tendency for negative covariance between long- and short-chain CHCs in males. Intersexual genetic covariances were often weak and frequently differed in sign. These findings are novel and significant, highlighting the previously unexplored genetic architecture of CHCs in D. simulans and suggest that this architecture may facilitate sex-specific CHC evolution.
Abstract.
Author URL.
Rostant WG, Wedell N, Hosken DJ (2012). Transposable elements and insecticide resistance.
Adv Genet,
78, 169-201.
Abstract:
Transposable elements and insecticide resistance.
Transposable elements (TEs) are mobile DNA sequences that are able to copy themselves within a host genome. They were initially characterized as selfish genes because of documented or presumed costs to host fitness, but it has become increasingly clear that not all TEs reduce host fitness. A good example of TEs benefiting hosts is seen with insecticide resistance, where in a number of cases, TE insertions near specific genes confer resistance to these man-made products. This is particularly true of Accord and associated TEs in Drosophila melanogaster and Doc insertions in Drosophila simulans. The first of these insertions also has sexually antagonistic fitness effects in the absence of insecticides, and although the magnitude of this effect depends on the genetic background in which Accord finds itself, this represents an excellent example of intralocus sexual conflict where the precise allele involved is well characterized. We discuss this finding and the role of TEs in insecticide resistance. We also highlight areas for further research, including the need for surveys of the prevalence and fitness consequences of the Doc insertion and how Drosophila can be used as models to investigate resistance in pest species.
Abstract.
Author URL.
Brown AR, Bickley LK, Le Page G, Hosken DJ, Paull GC, Hamilton PB, Owen SF, Robinson J, Sharpe AD, Tyler CR, et al (2011). Are toxicological responses in laboratory (inbred) zebrafish representative of those in outbred (wild) populations? - a case study with an endocrine disrupting chemical.
Environ Sci Technol,
45(9), 4166-4172.
Abstract:
Are toxicological responses in laboratory (inbred) zebrafish representative of those in outbred (wild) populations? - a case study with an endocrine disrupting chemical.
Laboratory animals tend to be more inbred and less genetically diverse than wild populations, and thus may differ in their susceptibility to chemical stressors. We tested this hypothesis by comparing the responses of related inbred (theoretical inbreeding F(IT) = n + 0.25) and outbred (F(IT) = n) zebrafish (Danio rerio) WIK/Wild family lines to an endocrine disrupting chemical, clotrimazole. Exposure of inbred and outbred zebrafish to 2.9 μg clotrimazole/L had no effect on survival, growth, or gonadal development. Exposure of both lines to 43.7 μg clotrimazole/L led to male-biased sex ratios compared with controls (87% versus 55% and 92% vs 64%, for inbred and outbred males, respectively), advanced germ cell development, and reduced plasma 11-ketotestosterone concentrations in males. However, outbred males (but not inbred males) developed testis that were more than twice the weight of controls, which corresponded with a proliferation of Leydig cells and maintenance of the expression (rather than down-regulation occurring in inbreds) of gonadal aromatase (cyp19a1a) and insulin-like growth factor (igf1). Our results illustrate that the effects of an endocrine disrupting chemical (clotrimazole) on some end points (here testis development) can differ between inbred and outbred zebrafish. This highlights the need for reporting pedigree/genetic information and consistency in the responses of laboratory animals (e.g. by using model compounds as positive controls).
Abstract.
Author URL.
Smith DT, Hosken DJ, Rostant WG, Yeo M, Griffin RM, Bretman A, Price TAR, Ffrench-Constant RH, Wedell N (2011). DDT resistance, epistasis and male fitness in flies.
J Evol Biol,
24(6), 1351-1362.
Abstract:
DDT resistance, epistasis and male fitness in flies.
In Drosophila melanogaster, the DDT resistance allele (DDT-R) is beneficial in the presence of DDT. Interestingly, DDT-R also elevates female fitness in the absence of DDT and existed in populations before DDT use. However, DDT-R did not spread regardless of DDT-independent selective advantages in females. We ask whether sexual antagonism could explain why DDT-R did not spread before pesticide use. We tested pre- and post-copulatory male fitness correlates in two genetic backgrounds into which we backcrossed the DDT-R allele. We found costs to DDT-R that depended on the genetic background in which DDT-R was found and documented strong epistasis between genetic background and DDT-R that influenced male size. Although it remains unclear whether DDT-R is generally sexually antagonistic, or whether the fitness costs noted would be sufficient to retard the spread of DDT-R in the absence of DDT, general fitness advantages to DDT-R in the absence of DDT may be unlikely.
Abstract.
Author URL.
Bambini L, Kofoky AF, Mbohoahy T, Ralisata M, Manjoazy T, Hosken DJ, Jenkins RKB (2011). Do bats need trees? habitat use of two malagasy hipposiderid bats triaenops furculus and T. menamena in the dry Southwest.
Hystrix,
22(1), 81-92.
Abstract:
Do bats need trees? habitat use of two malagasy hipposiderid bats triaenops furculus and T. menamena in the dry Southwest
Habitat degradation and loss threaten the survival of many bat species. Recent studies in Madagascar however have found some species are present in areas of low forest cover even though their echolocation calls and wing morphology suggest they are able to forage in forests. The present study investigated habitat use and prey selection in two sympatric hipposiderid bats, Triaenops furculus and T. menamena, in the dry southwest of Madagascar. The study colony occupied a cave in limestone karst surrounded by intact spiny bush and several secondary or degraded habitats. We used bat detectors and radiotracking to determine habitat use, and faecal analysis and invertebrate sampling to assess prey selection. Spiny bush, the dominant habitat type in the study area, was used less than predicted from its availability, based on satellite imagery and ground-based habitat mapping. Areas containing large trees were used by radiotracked bats in approximate proportion to their availability and acoustic sampling revealed highest bat activity in this habitat. The radio-tracked individuals used agricultural land more than expected from its availability. A significant difference was found in the proportion of Lepidoptera in the faeces of the two species, with T furculus showing a preference for moths. Triaenops furculus also selected Coleoptera, whereas T. menamena preferred mainly Hemiptera. While this study did not identify a strong association with forested habitats in T. furculus or T. menamena, it remains to be established whether the bats forage in a sub-optimal habitat due to their preference for roosting in the nearby karst caves.
Abstract.
Hosken DJ (2011). Gene duplication might not resolve intralocus sexual conflict.
Trends Ecol Evol,
26(11), 556-557.
Author URL.
Okada K, Pitchers WR, Sharma MD, Hunt J, Hosken DJ (2011). Longevity, calling effort, and metabolic rate in two populations of cricket.
Behavioral Ecology and Sociobiology,
65(9), 1773-1778.
Abstract:
Longevity, calling effort, and metabolic rate in two populations of cricket
Intraspecific variation in a resting metabolic rate (RMR) is likely to be an important determinant of energetic-resource use and may influence the resources subsequently available for allocation to traits not directly associated with somatic maintenance. The influence of RMR on resource availability could be especially important for condition-dependent sexual traits, such as cricket calls, that are themselves energetically costly to produce. RMR may also be associated with longevity, either negatively because individuals with a high RMR burn resources faster and die young, or positively as individuals with high RMR are more able to accrue resources to fuel survival. Additionally, the associations between RMR and other characters may vary across populations if differential selection or drift shapes these traits. Here we tested for differences in RMR, body mass, calling effort, and longevity in two populations of cricket Gryllodes sigillatus and then evaluated the potential influence of RMR on calling and longevity. We find that RMR, calling effort, and longevity varied across populations, but mass did not. Controlling for population and mass, RMR was not significantly associated with calling effort, but was negatively associated with longevity. These findings suggest that male crickets that live fast die young. © 2011 Springer-Verlag.
Abstract.
Okada K, Blount JD, Sharma MD, Snook RR, Hosken DJ (2011). Male attractiveness, fertility and susceptibility to oxidative stress are influenced by inbreeding in Drosophila simulans.
J Evol Biol,
24(2), 363-371.
Abstract:
Male attractiveness, fertility and susceptibility to oxidative stress are influenced by inbreeding in Drosophila simulans.
Inbreeding frequently leads to inbreeding depression, a reduction in the trait values of inbred individuals. Inbreeding depression has been documented in sexually selected characters in several taxa, and while there is correlational evidence that male fertility is especially susceptible to inbreeding depression, there have been few direct experimental examinations of this. Here, we assessed inbreeding depression in male fertility and a range of other male fitness correlates in Drosophila simulans. We found that male fertility and attractiveness were especially susceptible to inbreeding depression. Additionally, levels of testicular oxidative stress were significantly elevated in inbred males, although sperm viability did not differ between inbred and outbred males. Copulation duration, induction of oviposition, and the proportion of eggs hatching did not differ for females mated to inbred or outbred males. Nevertheless, our results clearly show that key male fitness components are impaired by inbreeding and provide evidence that aspects of male fertility are especially susceptible to inbreeding depression.
Abstract.
Author URL.
Sinclair BJ, Bretman A, Tregenza T, Tomkins JL, Hosken DJ (2011). Metabolic rate does not decrease with starvation in Gryllus bimaculatus when changing fuel use is taken into account.
Physiological Entomology,
36(1), 84-89.
Abstract:
Metabolic rate does not decrease with starvation in Gryllus bimaculatus when changing fuel use is taken into account
Many behavioural traits are considered to be condition-dependent, reflecting the differential allocation of resources to fitness-related traits and maintenance, although the physiological underpinnings of condition dependence are not well understood. In the present study, the hypothesis that condition dependence in male Gryllus bimaculatus De Geer is mediated by a decrease in metabolic rate with declining condition is tested. CO2 production is measured by flow-through respirometry, with insect condition manipulated through starvation. Crickets starved for 7 days have lower CO2 emission rates than individuals starved for only 24 h. However, carbohydrate reserves are depleted in the first 3 days, suggesting that the initial metabolism is primarily fuelled by carbohydrate, with a shift to lipid stores after 3 days. If the metabolic rate is estimated using respiratory quotients reflecting this shift in fuels, there is no difference in metabolic rate between crickets starved for 24 h and 7 days, suggesting that metabolic rate does not decrease with declining condition. This implies that a decrease in metabolic rate during starvation may not be a general pattern in insects, and emphasizes the need to consider fuel use during metabolic rate estimation in starvation studies. © 2010 the Authors. Physiological Entomology © 2010 the Royal Entomological Society.
Abstract.
Sharma MD, Tregenza T, Hosken DJ (2011). Sex combs, allometry, and asymmetry in Drosophila.
Biological Journal of the Linnean Society,
103(4), 923-934.
Abstract:
Sex combs, allometry, and asymmetry in Drosophila
There has been recent debate about the expected allometry of sexually-selected traits. Although sexually-selected traits exhibit a diversity of allometric patterns, signalling characters are frequently positively allometric. By contrast, insect genitalia tend to be negatively allometric, although the allometry of nongenital sexually-selected characters in insects is largely unknown (with some notable exceptions). It has also been suggested that there should be a negative association between the asymmetry and size of bilaterally-paired, sexually-selected traits, although this claim is controversial. We assessed the allometry and asymmetry (fluctuating asymmetry, FA) of a nongenital contact-courtship structure, the sex comb, in replicate populations of three species of Drosophila (we also measured wing FA). Sex combs are sexually-selected characters used to grasp the female's abdomen and genitalia and to spread her wings prior to and during copulation. Although species differed in the size of the sex combs, all combs were positively allometric, and comb allometry did not generally differ significantly between species or populations. Comb and wing asymmetry did vary across species, although not across populations of the same species. However, FA was trait specific and was never negatively associated with trait size. © 2011 the Linnean Society of London.
Abstract.
Hosken DJ, House CM (2011). Sexual selection.
Curr Biol,
21(2), R62-R65.
Abstract:
Sexual selection.
Sexual selection is a concept that has probably been misunderstood and misrepresented more than any other idea in evolutionary biology, confusion that continues to the present day. We are not entirely sure why this is, but sexual politics seems to have played its role, as does a failure to understand what sexual selection is and why it was initially invoked. While in some ways less intuitive than natural selection, sexual selection is conceptually identical to it, and evolution via either mechanism will occur given sufficient genetic variation. Recent claims that sexual selection theory is fundamentally flawed are simply wrong and ignore an enormous body of evidence that provides a bedrock of support for this major mechanism of organic evolution. In fact it is partly due to this solid foundation that current research has largely shifted from documenting whether or not sexual selection occurs, to addressing more complex evolutionary questions.
Abstract.
Author URL.
Mank JE, Hosken DJ, Wedell N (2011). Some inconvenient truths about sex chromosome dosage compensation and the potential role of sexual conflict.
Evolution,
65(8), 2133-2144.
Abstract:
Some inconvenient truths about sex chromosome dosage compensation and the potential role of sexual conflict.
Sex chromosome dosage compensation was once thought to be required to balance gene expression levels between sex-linked and autosomal genes in the heterogametic sex. Recent evidence from a range of animals has indicated that although sex chromosome dosage compensation exists in some clades, it is far from a necessary companion to sex chromosome evolution, and is in fact rather rare in animals. This raises questions about why complex dosage compensation mechanisms arise in some clades when they are not strictly needed, and suggests that the role of sex-specific selection in sex chromosome gene regulation should be reassessed. We show there exists a tremendous diversity in the mechanisms that regulate gene dosage and argue that sexual conflict may be an overlooked agent responsible for some of the variation seen in sex chromosome gene dose regulation.
Abstract.
Author URL.
Snook RR, Hosken DJ, Karr TL (2011). The biology and evolution of polyspermy: insights from cellular and functional studies of sperm and centrosomal behavior in the fertilized egg.
Reproduction,
142(6), 779-792.
Abstract:
The biology and evolution of polyspermy: insights from cellular and functional studies of sperm and centrosomal behavior in the fertilized egg.
Recent studies of centrosome biogenesis, microtubule dynamics, and their management point to their role in mediating conditions such as aging and cancer. Centrosome dysfunction is also a hallmark of pathological polyspermy. Polyspermy occurs when the oocyte is penetrated by more than one sperm and can be pathological because an excess of centrosomes compromises development. However, in some taxa, multiple sperm enter the egg with no apparent adverse effect on zygote viability. Thus, some taxa can manage excess centrosomes and represent cases of non-pathological polyspermy. While these two forms of polyspermy have long been known, we argue that there is limited understanding of the proximate and ultimate processes that underlie this taxonomic variation in the outcome of polyspermy and that studying this variation could help uncover the control and role(s) of centrosomes during fertilization in particular, but also mitosis in general. To encourage such studies we: 1) describe taxonomic differences in the outcome of polyspermy, 2) discuss mechanistic aspects of reproductive biology that may contribute to the different consequences of polyspermy, and 3) outline the potential selective events that could lead to the evolution of variation in polyspermy outcomes. We suggest that novel insights into centrosome biology may occur by cooperative studies between reproductive and evolutionary biologists focusing on the mechanisms generating variation in the fitness consequences of polyspermy, and in the taxonomic distribution of all these events. The consequent discoveries of these studies may lead to informative insights into cancer and aging along with other centrosome-related diseases and syndromes.
Abstract.
Author URL.
Gay L, Hosken DJ, Eady P, Vasudev R, Tregenza T (2011). The evolution of harm--effect of sexual conflicts and population size.
Evolution,
65(3), 725-737.
Abstract:
The evolution of harm--effect of sexual conflicts and population size.
Conflicts of interest between mates can promote the evolution of male traits that reduce female fitness and that drive coevolution between the sexes. The rate of adaptation depends on the intensity of selection and its efficiency, which depends on drift and genetic variability. This leads to the largely untested prediction that coevolutionary adaptations such as those driven by sexual conflict should evolve faster in large populations. We tested this using the bruchid beetle Callosobruchus maculatus, a species where harm inflicted by males is well documented. Although most experimental evolution studies remove sexual conflict, we reintroduced it in populations in which it had been experimentally removed. Both population size and standing genetic variability were manipulated in a factorial experimental design. After 90 generations of relaxed conflict (monogamy), the reintroduction of sexual conflicts for 30 generations favored males that harmed females and females that were more resistant to the genital damage inflicted by males. Males evolved to become more harmful when population size was large rather than when initial genetic variation was enriched. Our study shows that sexual selection can create conditions in which males can benefit from harming females and that selection may tend to be more intense and effective in larger populations.
Abstract.
Author URL.
Gay L, Brown E, Tregenza T, Pincheira-Donoso D, Eady PE, Vasudev R, Hunt J, Hosken DJ (2011). The genetic architecture of sexual conflict: male harm and female resistance in Callosobruchus maculatus.
J Evol Biol,
24(2), 449-456.
Abstract:
The genetic architecture of sexual conflict: male harm and female resistance in Callosobruchus maculatus.
Males harm females during mating in a range of species. This harm is thought to evolve because it is directly or indirectly beneficial to the male, despite being costly to his mate. The resulting sexually antagonistic selection can cause sexual arms races. For sexually antagonistic co-evolution to occur, there must be genetic variation for traits involved in female harming and susceptibility to harm, but even then intersexual genetic correlations could facilitate or impede sexual co-evolution. Male Callosobruchus maculatus harm their mates during copulation by damaging the female's reproductive tract. However, there have been no investigations of the genetic variation in damage or in female susceptibility to damage, nor has the genetic covariance between these characters been assessed. Here, we use a full-sib/half-sib breeding design to show that male damage is heritable, whereas female susceptibility to damage is much less so. There is also a substantial positive genetic correlation between the two, suggesting that selection favouring damaging males will increase the prevalence of susceptible females. We also provide evidence consistent with intralocus sexual conflict in this species.
Abstract.
Author URL.
Taylor ML, Wedell N, Hosken DJ (2010). Attractive males do not sire superior daughters.
Evolutionary Ecology,
24(1), 195-205.
Abstract:
Attractive males do not sire superior daughters
Much of the recent work on the evolution of female choice has focused on the relative influence of direct and indirect benefits, and particularly whether direct costs can be offset by indirect benefits. Studies investigating whether attractive males benefit females by increasing the viability of their offspring often report mating advantages to sons consistent with the Fisher process, while detecting no or weak viability benefits. One potential reason for this is that sons may trade-off viability benefits with investment in costly traits that enhance mating success, leading to the suggestion that viability benefits may be better detected by examining daughters' fitness. Here we investigate the relationship between male attractiveness and daughters' fitness in Drosophila simulans. We measured daughter (and dam) lifetime reproductive success and longevity. We found no evidence that attractive males sire high fitness daughters. Additionally, neither daughters nor dams gained direct benefits from mating with attractive males. However, aspects of daughters' fitness were related to dam characters. © Springer Science+Business Media B.V. 2009.
Abstract.
Sharma MD, Tregenza T, Hosken DJ (2010). Female mate preferences in Drosophila simulans: evolution and costs.
J Evol Biol,
23(8), 1672-1679.
Abstract:
Female mate preferences in Drosophila simulans: evolution and costs.
Female mate preference is central to sexual selection, and all indirect benefit models require that there is genetic variation in female preference. This has rarely been tested however, with relatively few studies documenting heritable variation in female preference and even fewer that have directly selected on mate preference to unequivocally show that it can evolve. Additionally, costs of mate preference are poorly understood even though these have implications for preference evolution. We selected on female preference for ebony-males in replicate Drosophila simulans lines, and generated a rapid evolutionary response in both replicates, with the proportion of females mating with ebony-males increasing from approximately 5% to 30% after five generations of selection. This increase was independent of changes in ebony-males as only females were included in our selection regime. We could detect no cost to mate preference itself other than that associated with the fitness consequences of mating with ebony males.
Abstract.
Author URL.
Arnqvist G, Dowling DK, Eady P, Gay L, Tregenza T, Tuda M, Hosken DJ (2010). Genetic architecture of metabolic rate: environment specific epistasis between mitochondrial and nuclear genes in an insect.
Evolution,
64(12), 3354-3363.
Abstract:
Genetic architecture of metabolic rate: environment specific epistasis between mitochondrial and nuclear genes in an insect.
The extent to which mitochondrial DNA (mtDNA) variation is involved in adaptive evolutionary change is currently being reevaluated. In particular, emerging evidence suggests that mtDNA genes coevolve with the nuclear genes with which they interact to form the energy producing enzyme complexes in the mitochondria. This suggests that intergenomic epistasis between mitochondrial and nuclear genes may affect whole-organism metabolic phenotypes. Here, we use crossed combinations of mitochondrial and nuclear lineages of the seed beetle Callosobruchus maculatus and assay metabolic rate under two different temperature regimes. Metabolic rate was affected by an interaction between the mitochondrial and nuclear lineages and the temperature regime. Sequence data suggests that mitochondrial genetic variation has a role in determining the outcome of this interaction. Our genetic dissection of metabolic rate reveals a high level of complexity, encompassing genetic interactions over two genomes, and genotype × genotype × environment interactions. The evolutionary implications of these results are twofold. First, because metabolic rate is at the root of life histories, our results provide insights into the complexity of life-history evolution in general, and thermal adaptation in particular. Second, our results suggest a mechanism that could contribute to the maintenance of nonneutral mtDNA polymorphism.
Abstract.
Author URL.
Narraway C, Hunt J, Wedell N, Hosken DJ (2010). Genotype by envirnment interactions for female preference. Journal of Evolutionary Biology, 23, 2550-2557.
Harano T, Okada K, Nakayama S, Miyatake T, Hosken DJ (2010). Intralocus sexual conflict unresolved by sex-limited trait expression.
Curr Biol,
20(22), 2036-2039.
Abstract:
Intralocus sexual conflict unresolved by sex-limited trait expression.
Sexually antagonistic selection generates intralocus sexual conflict, an evolutionary tug-of-war between males and females over optimal trait values [1-4]. Although the potential for this conflict is universal, the evolutionary importance of intralocus conflict is controversial because conflicts are typically thought to be resolvable through the evolution of sex-specific trait development [1-8]. However, whether sex-specific trait expression always resolves intralocus conflict has not been established. We assessed this with beetle populations subjected to bidirectional selection on an exaggerated sexually selected trait, the mandible. Mandibles are only ever developed in males for use in male-male combat, and larger mandibles increase male fitness (fighting [9, 10] and mating success, as we show here). We find that females from populations selected for larger male mandibles have lower fitness, whereas females in small-mandible populations have highest fitness, even though females never develop exaggerated mandibles. This is because mandible development changes genetically correlated characters, resulting in a negative intersexual fitness correlation across these populations, which is the unmistakable signature of intralocus sexual conflict [1]. Our results show that sex-limited trait development need not resolve intralocus sexual conflict, because traits are rarely, if ever, genetically independent of other characters [11]. Hence, intralocus conflict resolution is not as easy as currently thought.
Abstract.
Author URL.
Brown EA, Gay L, Vasudev R, Tregenza T, Eady PE, Hosken DJ (2010). Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles (vol 103, pg 340, 2009).
HEREDITY,
105(6), 576-576.
Author URL.
Dobler R, Hosken DJ (2010). Response to selection and realized heritability of sperm length in the yellow dung fly (Scathophaga stercoraria).
Heredity (Edinb),
104(1), 61-66.
Abstract:
Response to selection and realized heritability of sperm length in the yellow dung fly (Scathophaga stercoraria).
Sperm length shows considerable phenotypic variation both inter- and intra-specifically, but a general explanation for this variation is lacking. In addition, our understanding of the genetic variation underlying sperm length variation is also limited because there have been few studies on the genetics of sperm size. One factor that could explain the variation in sperm length is that length influences sperm competitiveness, and there is some evidence for this. However, in yellow dung flies (Scathophaga stercoraria), microevolutionary responses to experimental variation at levels of sperm competition indicate that sperm length does not influence sperm competitiveness, although this lack of response may simply indicate sperm length lacks evolutionary potential (that is, it is constrained in some way), in spite of evidence that sperm length is heritable. Here we report on a laboratory study, in which we artificially selected upwards and downwards on sperm length in S. stercoraria. We found that sperm length significantly diverged after four generations of selection, but the response to selection was asymmetrical: upward selection generated a rapid response, but downward did not. We estimated the realized heritability of sperm length to be approximately 50%, which is consistent with previous sire-son estimates. We also assessed the fertility of males from upward and downward lines and found they did not differ. Results are discussed in the context of sperm competition.
Abstract.
Author URL.
Punzalan D, Hosken DJ (2010). Sexual dimorphism: why the sexes are (and are not) different.
Curr Biol,
20(22), R972-R973.
Abstract:
Sexual dimorphism: why the sexes are (and are not) different.
Sex differences often call sexual selection to mind; however, a new damselfly study cautions on being too hasty, and implicates viability selection in the evolution of male and female colouration.
Abstract.
Author URL.
Okada K, Hosken DJ (2010). Sperm competition: discrimination isn't always bad.
Curr Biol,
20(10), R444-R446.
Abstract:
Sperm competition: discrimination isn't always bad.
Observing sperm in competition has been limited by our ability to discriminate between males' sperm. Recent work has overcome this obstacle, while another study reports on seminal fluid with very specific spermicidal activity, suggesting discrimination is easy for some.
Abstract.
Author URL.
Ingleby FC, Hunt J, Hosken DJ (2010). The role of genotype-by-environment interactions in sexual selection.
J Evol Biol,
23(10), 2031-2045.
Abstract:
The role of genotype-by-environment interactions in sexual selection.
Genotype-by-environment interactions (GxEs) in naturally selected traits have been extensively studied, but the impact of GxEs on sexual selection has only recently begun to receive attention. Here, we review recent models and consider how GxEs might affect the evolution of sexual traits through influencing sexual signal reliability and also how GxEs may influence variation in sexually selected traits and the process of reproductive isolation. We then assess the current empirical literature on GxEs in sexual selection and conclude by highlighting areas that need additional work. Research on GxEs and sexual selection is an important new area of study for the discipline, which has largely focused on relatively simple mate choice/competition scenarios to date. Investigators now need to apply this knowledge to more complex, but realistic, situations, to more fully explore the evolution of sexual traits, and in this review we suggest potentially useful directions for future research.
Abstract.
Author URL.
Hosken DJ, Kunz TH (2009). But is it male lactation or not?. Trends Ecol Evol, 24(7), 355-355.
Gay L, Eady PE, Vasudev R, Hosken DJ, Tregenza T (2009). Costly sexual harassment in a beetle.
Physiological Entomology,
34(1), 86-92.
Abstract:
Costly sexual harassment in a beetle
The optimal number of mating partners for females rarely coincides with that for males, leading to sexual conflict over mating frequency. In the bruchid beetle Callosobruchus maculatus, the fitness consequences to females of engaging in multiple copulations are complex, with studies demonstrating both costs and benefits to multiple mating. However, females kept continuously with males have a lower lifetime egg production compared with females mated only once and then isolated from males. This reduction in fitness may be a result of damage caused by male genitalia, which bear spines that puncture the female's reproductive tract, and/or toxic elements in the ejaculate. However, male harassment rather than costs of matings themselves could also explain the results. In the present study, the fitness costs of male harassment for female C. maculatus are estimated. The natural refractory period of females immediately after their first mating is used to separate the cost of harassment from the cost of mating. Male harassment results in females laying fewer eggs and this results in a tendency to produce fewer offspring. The results are discussed in the context of mate choice and sexual selection. © 2008 the Royal Entomological Society.
Abstract.
Gay L, Eady PE, Vasudev R, Hosken DJ, Tregenza T (2009). Does reproductive isolation evolve faster in larger populations via sexually antagonistic coevolution?.
Biol Lett,
5(5), 693-696.
Abstract:
Does reproductive isolation evolve faster in larger populations via sexually antagonistic coevolution?
Sexual conflict over reproductive investment can lead to sexually antagonistic coevolution and reproductive isolation. It has been suggested that, unlike most models of allopatric speciation, the evolution of reproductive isolation through sexually antagonistic coevolution will occur faster in large populations as these harbour greater levels of standing genetic variation, receive larger numbers of mutations and experience more intense sexual selection. We tested this in bruchid beetle populations (Callosobruchus maculatus) by manipulating population size and standing genetic variability in replicated lines derived from founders that had been released from sexual conflict for 90 generations. We found that after 19 generations of reintroduced sexual conflict, none of our treatments had evolved significant overall reproductive isolation among replicate lines. However, as predicted, measures of reproductive isolation tended to be greater among larger populations. We discuss our methodology, arguing that reproductive isolation is best examined by performing a matrix of allopatric and sympatric crosses whereas measurement of divergence requires crosses with a tester line.
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Author URL.
Brown AR, Hosken DJ, Balloux F, Bickley LK, LePage G, Owen SF, Hetheridge MJ, Tyler CR (2009). Genetic variation, inbreeding and chemical exposure--combined effects in wildlife and critical considerations for ecotoxicology.
Philos Trans R Soc Lond B Biol Sci,
364(1534), 3377-3390.
Abstract:
Genetic variation, inbreeding and chemical exposure--combined effects in wildlife and critical considerations for ecotoxicology.
Exposure to environmental chemicals can have negative consequences for wildlife and even cause localized population extinctions. Resistance to chemical stress, however, can evolve and the mechanisms include desensitized target sites, reduced chemical uptake and increased metabolic detoxification and sequestration. Chemical resistance in wildlife populations can also arise independently of exposure and may be spread by gene flow between populations. Inbreeding-matings between closely related individuals-can have negative fitness consequences for natural populations, and there is evidence of inbreeding depression in many wildlife populations. In some cases, reduced fitness in inbred populations has been shown to be exacerbated under chemical stress. In chemical testing, both inbred and outbred laboratory animals are used and for human safety assessments, iso-genic strains (virtual clones) of mice and rats are often employed that reduce response variation, the number of animals used and associated costs. In contrast, for environmental risk assessment, strains of animals are often used that have been selectively bred to maintain heterozygosity, with the assumption that they are better able to predict adverse effects in wild, genetically variable, animals. This may not necessarily be the case however, as one outbred strain may not be representative of another or of a wild population. In this paper, we critically discuss relationships between genetic variation, inbreeding and chemical effects with the intention of seeking to support more effective chemical testing for the protection of wildlife.
Abstract.
Author URL.
Hosken DJ, Price TAR (2009). Genital evolution: the traumas of sex.
Curr Biol,
19(13), R519-R521.
Abstract:
Genital evolution: the traumas of sex.
Copulating males usually insert their penis into the female and ejaculate in her reproductive tract; but in some species, males are more invasive, puncturing the female body-wall and inseminating directly into her body-cavity. A spider has just been added to this list and new perspectives provided on why males harm females during copulation in the first place.
Abstract.
Author URL.
Martin OY, Hosken DJ (2009). Longevity and developmental stability in the dung fly Sepsis cynipsea, as affected by the ectoparasitic mite, Pediculoides mesembrinae.
J Insect Sci,
9, 1-9.
Abstract:
Longevity and developmental stability in the dung fly Sepsis cynipsea, as affected by the ectoparasitic mite, Pediculoides mesembrinae.
Fluctuating asymmetry (FA) is a widely employed measure of developmental stability. It has been found to increase with many stressors including parasite infection. Associations between parasites and FA may exist for several reasons in addition to parasites being the direct cause of increased FA. Developmentally stable individuals may have superior immune systems, and be less susceptible to parasite infection, and/or may be less exposed to parasites than developmentally unstable ones. Mites negatively impact host fitness in a number of insects, and if FA is a reflection of general genetic quality, as has been proposed, associations between mite number and FA are predicted. Potential relationships were investigated between an ectoparasitic mite, Pediculoides mesembrinae (Canestrini) (Phthiraptera: Menoponidae) and FA in the common dung fly Sepsis cynipsea (L.) (Diptera: Sepsidae). While it was found that mite infested flies died much faster than flies without mites, indicating that mites indeed stress their hosts, counter to expectations, no associations between mites and FA were found in any analyses. Additionally, FA in mite-infected flies generally did not differ from previously published FA data from uninfected S. cynipsea. Nevertheless, parasitized males tended to be somewhat less asymmetrical than non-parasitized males, but based on our data, it does not appear that mite infestation is generally associated with developmental stability in S. cynipsea.
Abstract.
Author URL.
Kunz TH, Hosken DJ (2009). Male lactation: why, why not and is it care?.
Trends Ecol Evol,
24(2), 80-85.
Abstract:
Male lactation: why, why not and is it care?
Mammals are characterised by their ability to provision offspring with milk, but lactation is normally restricted to females. Why do most males not share this trait? the morphological and physiological modifications necessary for male lactation are possible and, although restrictive, the ecological factors that could select for male lactation seem common enough. Until quite recently, there was no evidence for male lactation in wild mammals, but it has now been reported in two species of Old World fruit bats. Here we review mechanisms that can cause milk production in males and also consider the possibility that male lactation in these bats is a unique adaptive phenomenon.
Abstract.
Author URL.
Hosken DJ, Stockley P, Tregenza T, Wedell N (2009). Monogamy and the battle of the sexes.
Annu Rev Entomol,
54, 361-378.
Abstract:
Monogamy and the battle of the sexes.
Sexual conflict has been suggested to be important in the evolution of reproductive traits, with much recent theoretical and empirical evidence emphasizing its role in generating sexually antagonistic coevolution in the context of promiscuous mating. Here we shift attention to the role of sexual conflict in a monogamous mating context. Conflicts can arise, for example, when males are successful in imposing monandry at a cost to female fitness, or when females impose monogyny on males. Conflict over remating can also generate monogamy. For example, when males invest heavily in attempting to impose female monandry, the cost of their investment may prevent them from securing additional mates. We emphasize that sexual conflicts need not always generate sexually antagonistic coevolution, and that it is important to consider whether mating decisions are controlled primarily by males or females. Finally, we briefly discuss approaches to distinguish between conflict and classical modes of sexual selection, as this highlights difficulties associated with deciding whether monogamy is enforced by one sex or the other. We suggest that documenting the current fitness consequences of mate choice and mating patterns provides insight into the relative importance of classic and conflict modes of selection.
Abstract.
Author URL.
Hosken DJ (2009). More acclaim for Darwin's theory of sexual selection.
Nature,
458(7240).
Author URL.
Brown EA, Gay L, Vasudev R, Tregenza T, Eady PE, Hosken DJ (2009). Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles.
Heredity (Edinb),
103(4), 340-345.
Abstract:
Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles.
Reproduction can be costly and is predicted to trade-off against other characters. However, while these trade-offs are well documented for females, there has been less focus on aspects of male reproduction. Furthermore, those studies that have looked at males typically only investigate phenotypic associations, with the underlying genetics often ignored. Here, we report on phenotypic and genetic trade-offs in male reproductive effort in the seed beetle, Callosobruchus maculatus. We find that the duration of a male's first copulation is negatively associated with subsequent male survival, phenotypically and genetically. Our results are consistent with life-history theory and suggest that like females, males trade-off reproductive effort against longevity.
Abstract.
Author URL.
Higgins SL, Hosken DJ, Wedell N (2009). Phenotypic and genetic variation in male genitalia in the seedbug, Lygaeus equestris (Heteroptera).
Biological Journal of the Linnean Society,
98(2), 400-405.
Abstract:
Phenotypic and genetic variation in male genitalia in the seedbug, Lygaeus equestris (Heteroptera)
Male genitalia evolve through sexual selection and, in insects, tend to show negative static allometry, low phenotypic variation, and are usually relatively small. Much less is known about the genetic variation and heritability of male genitalia. Additionally, in instances where the intromittent organ is greatly elongated, it is unclear whether typical patterns of genital scaling and variation also apply. In the present study, we investigated the allometry, variation, and heritability of male genital length in the seedbug, Lygaeus equestris, a species with a greatly elongated intromittent organ (i.e. almost as long as male body size). We found that genital length was negatively allometric, in spite of its great length, and was no more variable than nongenital traits. Additionally, genital length was significantly heritable and had considerable evolvability. © 2009 the Linnean Society of London.
Abstract.
Hosken DJ, Martin OY, Wigby S, Chapman T, Hodgson DJ (2009). Sexual conflict and reproductive isolation in flies.
Biol Lett,
5(5), 697-699.
Abstract:
Sexual conflict and reproductive isolation in flies.
Sexual conflict is predicted to generate more rapid reproductive isolation between larger populations. While there is some empirical support for this, the data are inconsistent and, additionally, there has been criticism of some of the evidence. Here we reanalyse two experimental-evolution datasets using an isolation index widely applied in the speciation literature. We find evidence for reproductive isolation through sexual conflict in Sepsis cynipsea, but not in Drosophila melanogaster, and this occurred to a greater degree in larger populations, which is consistent with previous findings.
Abstract.
Author URL.
Taylor ML, Sharma MD, Hosken DJ (2009). Sexual selection in flies: a comparison of Drosophila simulans and D. melanogaster.
Animal Biology,
59(4), 391-402.
Abstract:
Sexual selection in flies: a comparison of Drosophila simulans and D. melanogaster
The traditional view of sexual selection via female mate choice is that female preference for certain males either has no net fitness cost or is beneficial to overall female fitness. A more contemporary view is that preferred males can at times reduce female fitness. This view has arisen from the realisation that conflict between the sexes is an inevitable feature of sexual reproduction, as each sex necessarily has a different agenda for maximizing fitness. Despite the hailing of sexual conflict as a paradigm shift and its prevalence in the recent sexual selection literature, compelling evidence that attractive males reduce female fitness remains taxonomically restricted. Here we review the findings of a series of investigations into the fitness consequences of female preference in the fly Drosophila simulans and compare them with its sibling species, D. melanogaster. We show that there are stark differences in the fitness consequences of mating with preferred males in the two species and discuss this contrast with reference to the current debates in the sexual selection literature. © 2009 Koninklijke Brill NV.
Abstract.
Gay L, Hosken DJ, Vasudev R, Tregenza T, Eady PE (2009). Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus.
J Evol Biol,
22(5), 1143-1150.
Abstract:
Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus.
The evolutionary factors affecting testis size are well documented, with sperm competition being of major importance. However, the factors affecting sperm length are not well understood; there are no clear theoretical predictions and the empirical evidence is inconsistent. Recently, maternal effects have been implicated in sperm length variation, a finding that may offer insights into its evolution. We investigated potential proximate and microevolutionary factors influencing testis and sperm size in the bruchid beetle Callosobruchus maculatus using a combined approach of an artificial evolution experiment over 90 generations and an environmental effects study. We found that while polyandry seems to select for larger testes, it had no detectable effect on sperm length. Furthermore, population density, a proximate indicator of sperm competition risk, was not significantly associated with sperm length or testis size variation. However, there were strong maternal effects influencing sperm length.
Abstract.
Author URL.
Pitnick S, Dobler R, Hosken DJ (2009). Sperm length is not influenced by haploid gene expression in the flies Drosophila melanogaster and Scathophaga stercoraria.
Proc Biol Sci,
276(1675), 4029-4034.
Abstract:
Sperm length is not influenced by haploid gene expression in the flies Drosophila melanogaster and Scathophaga stercoraria.
Recent theoretical models have postulated a role for haploid-diploid conflict and for kin selection favouring sperm cooperation and altruism in the diversification and specialization of sperm form. A critical assumption of these models-that haploid gene expression contributes to variation in sperm form-has never been demonstrated and remains contentious. By quantifying within-male variation in sperm length using crosses between males and females from populations that had been subjected to divergent experimental selection, we demonstrate that haploid gene expression does not contribute to variation in sperm length in both Drosophila melanogaster and Scathophaga stercoraria. This finding casts doubt on the importance of haploid-diploid conflict and kin selection as evolutionary influences of sperm phenotypes.
Abstract.
Author URL.
Pitnick S, Hosken DJ, Birkhead TR (2009). Sperm morphological diversity.
, 69-149.
Abstract:
Sperm morphological diversity
This chapter reviews the current knowledge of variation in sperm morphology over several levels of biological organization: variation within males (both within and across ejaculates), among males, among populations, and among species, along with prevailing hypotheses addressing the adaptive significance of such variation. With regard to developmental mechanisms, three aspects of the physiology of sperm production serve to limit within-ejaculate variation in sperm phenotypes. First, the location of the testes and numerous aspects of testicular physiology of some taxa are clearly adaptations to maintain a homeostatic developmental environment for sperm. Second, developing spermatids may share cytoplasm. Third, sperm phenotypes are predominantly determined by testicular gene expression and hence the diploid genome of the male. Variation across ejaculates but within males can involve several traits including sperm numbers, overall semen quality and individual sperm quality. A special case of intramale variation in sperm form is found in species with sperm heteromorphism, in which different sperm forms are regularly produced by individuals. Differences among males in sperm morphology may derive from both genetic and environmental influences. Theories of condition-dependence basically posit that fitness-related traits are to a large extent dependent on an organism's underlying condition. Conclusions drawn from studies of sperm diversification between natural populations are reinforced by experimental evolution studies of sperm morphology in laboratory populations, as these studies address the evolvability of sperm traits and the nature of selection underlying sperm diversification. Furthermore, a discussion of evolutionary causes and consequences of sperm diversification, along with suggestions of fruitful areas for future exploration is presented. © 2009 Copyright © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Lessells CM, Snook RR, Hosken DJ (2009). The evolutionary origin and maintenance of sperm: Selection for a small, motile gamete mating type.
, 43-67.
Abstract:
The evolutionary origin and maintenance of sperm: Selection for a small, motile gamete mating type
Sperm have three fundamental characteristics: they are small, they are motile, and they fuse disassortatively with eggs. Isogamy is generally accepted as the ancestral state and from this starting point, there are a number of different sequences by which sperm may have evolved, with any of the three characteristics of this sexual reproductive syndrome potentially having evolved first. One of the most striking features of the egg-sperm dichotomy is the massive size dimorphism. There are three general kinds of theory to explain the evolution of gamete dimorphism: gamete competition, sperm limitation, and intracellular conflict. In extant organisms, gamete dimorphism is always associated with the occurrence of two mating types with disassortative fusion. This linkage may have evolved in one of two general ways: first, mating types may have evolved before gamete dimorphism, as supported by the near-ubiquity of mating types irrespective of whether gametes are dimorphic. The evolutionary loss of motility in eggs (and the extreme specialization for motility in sperm of most species) is generally seen as the last step in the evolution of the egg-sperm dichotomy. The evolution of motility dimorphism might also be concomitant with that of size dimorphism, or it might have evolved after both size dimorphism and mating types. © 2009 Copyright © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Smith DT, Hosken DJ, Ffrench-Constant RH, Wedell N (2009). Variation in sex peptide expression in D. melanogaster.
Genet Res (Camb),
91(4), 237-242.
Abstract:
Variation in sex peptide expression in D. melanogaster.
Male Drosophila melanogaster transfers many accessory-gland proteins to females during copulation. Sex peptide (SP) is one of these and one of its main effects is to decrease female remating propensity. To date, there has been no investigation of genetic variation in SP-gene expression levels, or if such potential variation directly influences female remating behaviour. We assessed both these possibilities and found significant variation in expression levels of the SP gene across D. melanogaster isolines. A non-linear association between SP expression levels and female remating delay suggestive of disruptive selection on expression levels was also documented. Finally, while some isolines were infected with the endosymbiont Wolbachia, no association between Wolbachia and SP expression level was found.
Abstract.
Author URL.
Hosken DJ, Taylor ML, Hoyle K, Higgins S, Wedell N (2008). Attractive males have greater success in sperm competition.
Current Biology,
18(13).
Abstract:
Attractive males have greater success in sperm competition
While sexual selection is responsible for the rapid evolution of many characters [1,2], the precise relationship between pre- and post-copulatory sexual selection is unclear [3]. In some species, the two are positively associated and reinforce each other, while in others, the two bouts of selection are antagonistic and cancel each other out. Here we assessed the relationship between female preference for males and male fertilization success during sperm competition in the fly Drosophila simulans. We find that attractive males sired more offspring and also find a positive genetic correlation between male attractiveness and siring success. © 2008 Elsevier Ltd. All rights reserved.
Abstract.
Hosken DJ (2008). Clitoral variation says nothing about female orgasm. Evolution and Development, 10(4), 393-395.
Wright, L, Tregenza, T. Hosken, D.J. (2008). Inbreeding, inbreeding depression and extinction. Conservation Genetics, 9, 833-843.
Demont M, Blanckenhorn WU, Hosken DJ, Garner TWJ (2008). Molecular and quantitative genetic differentiation across Europe in yellow dung flies.
J Evol Biol,
21(6), 1492-1503.
Abstract:
Molecular and quantitative genetic differentiation across Europe in yellow dung flies.
Relating geographic variation in quantitative traits to underlying population structure is crucial for understanding processes driving population differentiation, isolation and ultimately speciation. Our study represents a comprehensive population genetic survey of the yellow dung fly Scathophaga stercoraria, an important model organism for evolutionary and ecological studies, over a broad geographic scale across Europe (10 populations from the Swiss Alps to Iceland). We simultaneously assessed differentiation in five quantitative traits (body size, development time, growth rate, proportion of diapausing individuals and duration of diapause), to compare differentiation in neutral marker loci (F(ST)) to that of quantitative traits (Q(ST)). Despite long distances and uninhabitable areas between sampled populations, population structuring was very low but significant (F(ST) = 0.007, 13 microsatellite markers; F(ST) = 0.012, three allozyme markers; F(ST) = 0.007, markers combined). However, only two populations (Iceland and Sweden) showed significant allelic differentiation to all other populations. We estimated high levels of gene flow [effective number of migrants (Nm) = 6.2], there was no isolation by distance, and no indication of past genetic bottlenecks (i.e. founder events) and associated loss of genetic diversity in any northern or island population. In contrast to the low population structure, quantitative traits were strongly genetically differentiated among populations, following latitudinal clines, suggesting that selection is responsible for life history differentiation in yellow dung flies across Europe.
Abstract.
Author URL.
Taylor ML, Wigmore C, Hodgson DJ, Wedell N, Hosken DJ (2008). Multiple mating increases female fitness in Drosophila simulans.
Animal Behaviour,
76(3), 963-970.
Abstract:
Multiple mating increases female fitness in Drosophila simulans
While polyandry is essentially ubiquitous across the animal kingdom, the net fitness consequences of multiple mating remain the subject of much debate. In some taxa the costs of multiple mating outweigh potential benefits, and large direct costs are unlikely to be compensated for by indirect benefits. Nevertheless, direct and indirect benefits potentially provide females with substantial fitness returns, and these are manifest in some species. We investigated some fitness costs and benefits of multiple mating in the fly Drosophila simulans. We compared the longevity and lifetime reproductive success of females with intermittent or continual exposure to males with those of singly mated females housed alone or housed with virgin females. We also compared the same fitness components in females mated once, twice and three times. We found no difference in the lifetime reproductive success of females housed intermittently with males and those housed continually with males, but females in these treatments produced more offspring than singly mated females (housed alone or with virgin females). However, females that were continually exposed to males died younger than females from any other treatment. We also found that females who mated more than once had higher lifetime reproductive success, and that number of matings had no influence on residual longevity. These results contrast somewhat with findings from Drosophila melanogaster, and suggest that while polyandry is beneficial for female D. simulans, male harassment can be costly. © 2008 the Association for the Study of Animal Behaviour.
Abstract.
Taylor ML, Wedell, N. Hosken, D.J. (2008). Sexual selection and female fitness in <em>Drosophila simulans</em>. Behavioral Ecology and Sociobiology, 62, 721-728.
Hosken, D.J. (2007). Evolution: good males are bad females. Current Biology, 17, R168-R170.
House, CM, Hunt, J. Hosken, D.J. (2007). Evolution: lending a helping hand in sperm competition?. Current Biology, R90-R92.
Teuschl Y, Hosken, D.J. Blanckenhorn, W.U. (2007). Is reduced female survival after mating a by-product of male-male competition in the dung fly <em>Sepsis cynipsea</em>?. BMC Evolutionary Biology, 7
Champion de Crespigny, F.E. & Hosken, D.J. (2007). Sexual selection: signals to die for. Current Biology, R853-R855.
Taylor, M, Wedell, N. Hosken, D.J. (2007). The heritability of attractiveness. Current Biology, 17, R959-R960.
Hosken, DJ, Tregenza, T. (2006). Evolution; Inbreeding, Multiple mating and Embryonic Aid. Current Biology, 16(6), R202-R203.
Lessells CM, Bennett ATD, Birkhead TR, Colegrave N, Dall SRX, Harvey P, Hatchwell B, Hosken DJ, et al (2006). Nothing new under the sun: social selection is part of sexual selection theory. Science, 311, 689-690.
Pizzari T, Birkhead, T.R. Blows, M.W. Brooks, R. Buchanan KL, Clutton-Brock TL, Harvey P, Hosken DJ, et al (2006). Reproductive behaviour: sexual selection remains the best explanation. Science, 311
Dall, SRX, McNamara, J.M. Wedell, N. Hosken, D.J. (2006). Sexual selection cannot be replaced by cooperative game theory (and it doesn't need replacing). Science, 311
Hodgson, DJ, Hosken, D.J. (2006). Sperm competition promotes the exploitation of rival ejaculates. Journal of Theoretical Biology, 243, 230-234.
Minder, A.M. Hosken DJ, Ward, P.I. (2005). Co-evolution of male and female reproductive characters across the <em>Scathophagidae</em>. Journal of Evolutionary Biology, 18, 60-69.
Hosken DJ, Tregenza T (2005). Evolution: do bad husbands make good fathers?.
Curr Biol,
15(20), R836-R838.
Abstract:
Evolution: do bad husbands make good fathers?
Males sometimes harm their mates as they seek to maximise the number of offspring they sire. But are females really suffering or do the benefits of having sons that inherit their father's manipulative traits make up for the costs? Three recent studies provide the first hard data addressing this issue, but they differ in their conclusions.
Abstract.
Author URL.
Hosken D, Snook, R. (2005). How Important is Sexual Conflict?. American Naturalist, 165, S1-S4.
Minder, A.M. Ward, P.I. Hosken, DJ (2005). Male genital allometry in <em>Scathophagidae</em> (<em>Diptera</em>). Evolutionary Ecology, 19, 501-515.
Hosken, D.J. Tregenza, T (2005). Mate choice; Been there, done that. Current Biology, 15(23), R959-R961.
Schwartzenbach G, Hosken, D.J. Ward, P.I. (2005). Sex and immunity in the yellow dung fly <em>Scathophaga stercoraria</em>. Journal of Evolutionary Biology, 18, 455-463.
Hosken, DJ, Stockley, P. (2005). Sexual Conflict. Current Biology, 15(14), R335-R336.
Tregenza, T. Hosken DJ (2005). Sexual selection: Do bad husbands make good fathers?. Current Biology, 15(20), R836-R838.
Hosken, D.J. (2005). Would you accept advice from a believer in santa?. Nature, 433
Lupold S, McElligott, A.G. Hosken, D.J. (2004). Bat genitalia; allometry, variation and good genes. Biological Journal of the Linnean Society, 83, 497-507.
Martin, OY, Hosken, D.J. (2004). Copulation reduces male but not female longevity in <em>Saltella sphondylli</em> (<em>Diptera; Sepsidae</em>). Journal of Evolutionary Biology, 17, 357-362.
Blanckenhorn WU, Hellriegel, B. Hosken, D.J. Jann, P. Altweg R, Ward PI (2004). Does testis size track expected mating success in yellow dung flies?. Functional Ecology, 18, 414-418.
Garner TWJ, Pearman, P.B. Gregory's, P.T. Tomio, G. Wischiowski SG, Hosken DJ (2004). Microsatellite markers developed from <em>Thamnophis elegans</em> and <em>Thamnophis sirtalis</em> and their utility in three species of garter snakes. Molecular Ecology Notes
Martin OY, Ward, P.I. Hosken DJ (2004). Post-copulatory sexual selection and female fitness in <em>Scathophaga stercoraria</em>. Proceedings of the Royal Society of London B, 271, 353-359.
Hosken DJ, Martin OY (2004). Reproductive consequences of population divergence through sexual conflict. Current Biology, 14(10), 906-910.
Hosken DJ, Stockley, P. (2004). Sexual selection and genital evolution. Trends in Ecology & Evolution, 19, 87-93.
Hosken DJ, Snook RR (2004). Sperm death & dumping in Drosophila. Nature, 428(6986), 939-941.
Hosken DJ, Garner, T.W.J. Blanckenhorn, W.U. (2003). Asymmetry, testis and sperm size in yellow dung flies. , 17, 231-236.
Hosken DJ, Stockley, P. (2003). Benefits of polyandry; a life history perspective. Evolutionary Biology, 33, 173-194.
Martin OY, Hosken, D.J. (2003). Costs and benefits of evolving under experimentally enforced polyandry or monogamy. Evolution, 57, 2765-2772.
Hosken DJ, Pitnick, S. (2003). Do queens select sperm?. Trends in Ecology & Evolution, 18
Hosken DJ, Pitnick S (2003). Do queens select sperm? [1] (multiple letters). Trends in Ecology and Evolution, 18(3), 107-108.
Hosken, D.J. Blanckenhorn WU (2003). Heritability of three condition surrogates in the yellow dung fly. Behavioral Ecology, 14(5), 612-618.
Martin OY, Leugger, R.R. Zeltner, N. Hosken, D.J. (2003). Male age, mating probability and mating costs in the fly <em>Sepsis cynipsea</em>. Evolutionary Ecology Research, 5, 119-129.
Tregenza T, Hosken DJ, Ward PI, Wedell N (2003). Maternal effects on offspring depend on female mating pattern and offspring environment in yellow dung flies. Evolution, 57(2), 297-304.
Martin, O.Y. Born, J. Huber, F. Hosken DJ (2003). Sexual conflict in <em>Sepsis cynipsea</em>: female reluctance, fertility and mate choice. Journal of Evolutionary Biology, 16, 485-490.
Hosken, D.J. (2003). Sperm Biology; Size indeed matters. Current Biology, 13, R355-R356.
Oppliger A, Naciri-Griven, Y. Ribi, G. Hosken, D.J. (2003). Sperm length influences fertilization success during sperm competition in the snail <em>Viviparus ater</em>. Molecular Ecology, 12, 485-492.
Hosken DJ, Garner, T.W.J. Tregenza, T. Wedell N, Ward PI (2003). Superior sperm competitors sire higher quality young. Proceedings of the Royal Society of London B, 270, 1933-1938.
Hosken DJ, Martin OY (2003). The evolution of reproductive isolation through sexual conflict. Nature, 423(6943), 979-982.
Martin OY, Hosken, D.J. (2002). Asymmetry and fitness in female yellow dung flies. Biological Journal of the Linnean Society, 76, 557-563.
Hosken, D.J. (2002). Culture gap; Physics still seeks its unifying theory. Nature, 419
Hosken DJ, Jones KE, Chipperfield K, Dixson A (2002). Erratum: is the bat os penis sexually selected? (Behavioral Ecology and Sociobiology (2001) 50 (450-460)). Behavioral Ecology and Sociobiology, 51(3), 302-307.
Hosken DJ, Blanckenhorn, W.U. Garner, T.W.J. (2002). Heteropopulation males have a fertilization advantage during sperm competition in the yellow dung fly (<em>Scathophaga stercoraria</em>). Proceedings of the Royal Society of London B, 269, 1701-1707.
Hosken DJ, Jones KE, Chipperfield K, Dixson A (2002). Is the bat os penis sexually selected? (vol 50, pg 450, 2001).
BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY,
51(3), 302-307.
Author URL.
Blanckenhoooorn WU, Ding, A. Ward, P.I. Meile, P. Martin OY, Hosken DJ (2002). Mating with a large male yellow dung fly: cost or benefit in terms of clutch size?. Evolutionary Ecology Research, 4, 1201-1207.
Ward PI, Wedell, N. Hosken, D.J. Tregenza T (2002). Measuring the sperm competition successes of field males of the yellow dung fly. Ecological Entomology, 27, 763-765.
Martin OY, Hosken, D.J. (2002). Strategic ejaculation in the common dung fly <em>Sepsis cynipsea</em>. Animal Behaviour, 63, 541-546.
Hosken DJ, Uhia, E. Ward, P.I. (2002). The function of female accessory reproductive gland secretion and a cost to polyandry in the yellow dung fly. Physiological Entomology, 27, 87-91.
Hosken DJ, Balloux, F. (2002). Thirty years of evolution in Darwin's finches. Trends in Ecology & Evolution, 17(10), 447-448.
Hosken DJ, Ward, P.I. (2001). Experimental evidence for testis size evolution via sperm competition. Ecology Letters, 4, 10-13.
Hosken, D.J. (2001). Hidden change; cryptic evolution in flycatchers. Trends in Ecology & Evolution, 16(11).
Hosken DJ, Jones, K.E. Chipperfield, K. Dixson, A. (2001). Is the bat os penis sexually selected?. Behavioral Ecology and Sociobiology, 50, 450-460.
Hosken, D.J. (2001). Sex and death microevolutionary trade-offs between reproductive and immune investment in dung flies. Current Biology, 11(10), R379-R380.
Hosken DJ, Garner TWJ, Ward PI (2001). Sexual conflict selects for male and female reproductive characters. Current Biology, 11(7), 489-493.
Hosken, D.J. (2001). Size and fluctuating asymmetry in sexually selective traits. Animal Behaviour, 62, 603-605.
Hosken DJ, O'Shea, J.E. (2001). Sperm production and immune function in two Australian bats, <em>Chalinolobus morio</em> and <em>Nyctophilus geoffroyi</em>. Ethology Ecology & Evolution, 13, 173-180.
Hosken DJ, Ward, P.I. (2000). Copula in yellow dung flies (<em>Scathophaga stercoraria</em>):\r
investigating sperm competition models by histological observation. Journal of Insect Physiology, 46, 1355-1363.
Hosken DJ, Blanckenhorn, W.U. Ward, P.I. (2000). Developmental stability in yellow dung flies (<em>scathophaga stercoraria</em>); fluctuating asymmetry heterzygosity and environmental stresses. Journal of Evolutionary Biology, 13, 919-926.
Garner TWJ, Brinkmann, H. Gerlach, G. Meyer, A. Ward PI, Sporri M, Hosken DJ (2000). Polymorphic DNA microsatellites identified in the yellow dung fly (<em>Scathophaga stercoraria</em>). Molecular Ecology, 9, 2207-2208.
Hosken, D.J. Martin, O.Y. Reim, C. (2000). The cost of copulating in the dung fly <em>Sepsis cynipsea</em>. Behavioral Ecology, 13(3), 353-358.
Hosken DJ, Ward, P.I. (1999). Female accessory reproductive gland activity in the yellow dung fly <em>Scathophaga stercoraria</em> (L.). Journal of Insect Physiology, 45, 800-814.
Hosken DJ, Blanckenhorn, W.U. (1999). Female, multiple mating, inbreeding avoidance,and fitness; it is not only the magnitude of costs and benefits that counts. Behavioral Ecology, 10(4), 462-464.
Hosken DJ, Meyer, E.P. Ward, O.I. (1999). Internel female reproductive anatomy and genetal interactions during copula in the yellow dung fly, <em>Scathophaga stercoraria</em> (<em>Diptera; scathophagidar</em>). Canadian Journal of Zoology, 77, 1975-1983.
Hosken DJ, Withers, P.C. (1999). Metabolic Physiology of Euthermic and Torpid Lesser Long-Eared Bats, <em>Nyctophilus geoffroyi</em> (<em>Chiroptera; vesperitlionidae</em>). Journal of Mammalogy, 80(1), 42-52.
Hosken, D.J. (1999). Sperm displacement in yellow dung flies;a role for females. Trends in Ecology & Evolution, 14, 251-252.
Oppliger A, Hosken, D.J. Ribi, G. (1998). Snail sperm production characteristics vary\r
with sperm competition risk. Proceedings of the Royal Society of London B, 265, 1527-1534.
Hosken DJ, Stockley, P. (1998). Sperm counts. Trends in Ecology & Evolution, 13, 91-92.
Hosken, D.J. (1998). Sperm fertility and skewed paternity during sperm competition in the Australian long-eared bat <em>Nyctophilus geoffroyi</em> (<em>Chiroptera; vespertilionidae</em>). Journal of Zoology (London), 245, 93-100.
Hosken, D.J. (1998). Testes mass in megachiropteran bats varies in acccordance with sperm competition theory. Behavioral Ecology and Sociobiology, 44, 169-177.
Hosken DJ, Blackberry, M.A. Stewart, T.B. Stucki, A.F. (1998). The male reproductive cycle of three species of Austalian verpertilionid bat. Journal of Zoology (London), 245, 261-270.
Hosken DJ (1997). Erratum: Sperm competition in bats (Proceedings of the Royal Society of London (1997) March, 264 (385-392)). Proceedings of the Royal Society B: Biological Sciences, 264(1389).
Hosken, D.J. (1997). Reproduction and the female reproductive cycle of <em>Nyctophilus geoffroyi</em> and <em>N. major</em> from south-western Australia. Australian Journal of Zoology, 45, 489-504.
Hosken, D.J. (1997). Seasonal changes in testis mass and epididymal volume in the greater long-eared bat, <em>Nyctophilus timoriensis</em> (<em>major</em>), from the goldfields region of Western Australia. Australian Mammology, 20, 121-122.
Hosken, D.J. (1997). Sperm competition in bats. Proceedings of the Royal Society of London B, 264, 385-392.
Hosken DJ, Withers, P.C. (1997). Temperature regulation and metabolism of an Australian bat, <em>Chalinolobus gouldii</em> (<em>Chiroptera: Vespertilionidae</em>) when euthermic and torpid. Journal of Comparative Physiology B, 167, 71-80.
Hosken, D.J. (1997). Thermal biology and metabolism of the greater long-eared bat, <em>Nyctophilus major</em> (<em>timoriensis</em>) (<em>Chiroptera: Vespertilionidae</em>). Australian Journal of Zoology, 45, 145-156.
Hosken DJ, O'Shea, J.E. Blackberry, M.A. (1996). Blood plasma concentrations of progesterone, sperm storage and sperm viability and fertility in Gould's wattled bat (Chalinolobus gouldii) (Chiroptera: Vespertilionidae). Journal of Reproductive Fertility, 108, 171-177.
Hosken, D.J. (1996). Roost selection by the lesser long-eared bat, <em>Nyctophilus geoffroyi</em>, and greater long-eared bat, <em>N. major</em>, (<em>Chiroptera: Vespertilionidae</em>) in Banksia woodlands. Journal of the Royal Society of Western Australia, 79, 211-216.
Hosken DJ, Bailey, W.J. O'Shea, J.E. Roberts, J.D. (1994). Localisation of insect calls by the bat <em>Nyctophilus geoffroyi</em> (<em>Chiroptera: Vespertilionidae</em>): a laboratory study. Australian Journal of Zoology, 42, 177-184.
Simmons LW, Llorens, T. Schinzig, M. Hosken D, Craig M (1994). Sperm competition selects for male mate choice and protandry in the bushcricket, <em>Requena verticalis</em> (<em>Orthoptera;Tettigoniidae</em>). Animal Behaviour, 47, 117-122.
Simmons LW, Craig, M. Llorens, T. Schinzig, M. Hosken D (1993). Buschcricket Spermatophores vary in accord with Sperm Competition and parental investment theory. Proceedings of the Royal Society of London B, 251(1332), 183-186.
Chapters
Hosken DJ, Hunt J (2014). Conclusions and Final Thoughts. In (Ed) Genotype-by-Environment Interactions and Sexual Selection, 331-334.
Ingleby FC, Hosken DJ, Hunt J (2014). Sexual Selection and Genotype-by-Environment Interactions in Drosophila Cuticular Hydrocarbons. In (Ed)
Genotype-by-Environment Interactions and Sexual Selection, 265-281.
Abstract:
Sexual Selection and Genotype-by-Environment Interactions in Drosophila Cuticular Hydrocarbons
Abstract.
Lessells CM, Snook RR, Hosken DJ (2009). 2 the evolutionary origin and maintenance of sperm selection for a small, motile gamete mating type. In (Ed) Sperm Biology, 43-67.
Pitnick S, Hosken DJ, Birkhead TR (2009). 3 Sperm morphological diversity. In (Ed) Sperm Biology, 69-149.
Publications by year
In Press
Singh KS, Hosken DJ, Wedell N, ffrench-Constant R, Bass C, Baxter S, Paszkiewicz K, Sharma MD (In Press). <i>De novo</i> genome assembly of the meadow brown butterfly, <i>Maniola jurtina</i>.
Abstract:
De novo genome assembly of the meadow brown butterfly, Maniola jurtina
AbstractBackgroundMeadow brown butterflies (Maniola jurtina) on the Isles of Scilly represent an ideal model in which to dissect the links between genotype, phenotype and long-term patterns of selection in the wild - a largely unfulfilled but fundamental aim of modern biology. To meet this aim, a clear description of genotype is required.FindingsHere we present the draft genome sequence of M. jurtina to serve as an initial genetic resource for this species. Seven libraries were constructed using DNA from multiple wild caught females and sequenced using Illumina, PacBio RSII and MinION technology. A novel hybrid assembly approach was employed to generate a final assembly with an N50 of 214 kb (longest scaffold 2.9 Mb). The genome encodes a total of 36,294 genes. 90.3% and 88.7% of core BUSCO (Benchmarking Universal Single-Copy Orthologs) Arthropoda and Insecta gene sets were recovered as complete single-copies from this assembly. Comparisons with 17 other Lepidopteran species placed 86.5% of the assembled genes in orthogroups.ConclusionsOur results provide the first high-quality draft genome and annotation of the butterfly M. jurtina.
Abstract.
Archer R, Recker M, Duffy E, Hosken D (In Press). Intralocus sexual conflict can resolve the male-female health-survival paradox. Nature Communications
Hosken DJ, Alonzo SH, Wedell N (In Press). Why aren’t females ornamented more often?.
2022
Carey MR, Archer CR, Rapkin J, Castledine M, Jensen K, House CM, Hosken DJ, Hunt J (2022). Mapping sex differences in the effects of protein and carbohydrates on lifespan and reproduction in Drosophila melanogaster: is measuring nutrient intake essential?.
Biogerontology,
23(1), 129-144.
Abstract:
Mapping sex differences in the effects of protein and carbohydrates on lifespan and reproduction in Drosophila melanogaster: is measuring nutrient intake essential?
Understanding how diet affects reproduction and survival is a central aim in evolutionary biology. Although this relationship is likely to differ between the sexes, we lack data relating diet to male reproductive traits. One exception to this general pattern is Drosophila melanogaster, where male dietary intake was quantified using the CApillary FEeder (CAFE) method. However, CAFE feeding reduces D. melanogaster survival and reproduction, so may distort diet-fitness outcomes. Here, we use the Geometric Framework of Nutrition to create nutrient landscapes that map sex-specific relationships between protein, carbohydrate, lifespan and reproduction in D. melanogaster. Rather than creating landscapes with consumption data, we map traits onto the nutrient composition of forty agar-based diets, generating broad coverage of nutrient space. We find that male and female lifespan was maximised on low protein, high carbohydrate blends (~ 1P:15.9C). This nutrient ratio also maximised male reproductive rates, but females required more protein to maximise daily fecundity (1P:1.22C). These results are consistent with CAFE assay outcomes. However, the approach employed here improved female fitness relative to CAFE assays, while effects of agar versus CAFE feeding on male fitness traits depended on the nutrient composition of experimental diets. We suggest that informative nutrient landscapes can be made without measuring individual nutrient intake and that in many cases, this may be preferable to using the CAFE approach. The most appropriate method will depend on the question and species being studied, but the approach adopted here has the advantage of creating nutritional landscapes when dietary intake is hard to quantify.
Abstract.
Author URL.
Laugen AT, Hosken DJ, Reinhold K, Schwarzenbach GA, Hoeck PEA, Bussière LF, Blanckenhorn WU, Lüpold S (2022). Sperm competition in yellow dung flies: No consistent effect of sperm size. Journal of Evolutionary Biology, 35(10), 1309-1318.
2021
Lymbery SJ, Tomkins JL, Buzatto BA, Hosken DJ (2021). Kin-mediated plasticity in alternative reproductive tactics.
Proceedings of the Royal Society B: Biological Sciences,
288(1956), 20211069-20211069.
Abstract:
Kin-mediated plasticity in alternative reproductive tactics
Conditional strategies occur when the relative fitness pay-off from expressing a given phenotype is contingent upon environmental circumstances. This conditional strategy model underlies cases of alternative reproductive tactics, in which individuals of one sex employ different means to obtain reproduction. How kin structure affects the expression of alternative reproductive tactics remains unexplored. We address this using the miteRhizoglyphus echinopus, in which large males develop into aggressive ‘fighters’ and small males develop into non-aggressive ‘scramblers.’ Because only fighters kill their rivals, they should incur a greater indirect fitness cost when competing with their relatives, and thus fighter expression could be reduced in the presence of relatives. We raised mites in full-sibling or mixed-sibship groups and found that fighters were more common at higher body weights in full-sibling groups, not less common as we predicted (small individuals were almost exclusively scramblers in both treatments). This result could be explained if relatedness and cue variability are interpreted signals of population density, since fighters are more common at low densities in this species. Alternatively, our results may indicate that males compete more intensely with relatives in this species. We provide the first evidence of kin-mediated plasticity in the expression of alternative reproductive tactics.
Abstract.
Okada K, Katsuki M, Sharma MD, Kiyose K, Seko T, Okada Y, Wilson AJ, Hosken DJ (2021). Natural selection increases female fitness by reversing the exaggeration of a male sexually selected trait.
Nature Communications,
12(1).
Abstract:
Natural selection increases female fitness by reversing the exaggeration of a male sexually selected trait
AbstractTheory shows how sexual selection can exaggerate male traits beyond naturally selected optima and also how natural selection can ultimately halt trait elaboration. Empirical evidence supports this theory, but to our knowledge, there have been no experimental evolution studies directly testing this logic, and little examination of possible associated effects on female fitness. Here we use experimental evolution of replicate populations of broad-horned flour beetles to test for effects of sex-specific predation on an exaggerated sexually selected male trait (the mandibles), while also testing for effects on female lifetime reproductive success. We find that populations subjected to male-specific predation evolve smaller sexually selected mandibles and this indirectly increases female fitness, seemingly through intersexual genetic correlations we document. Predation solely on females has no effects. Our findings support fundamental theory, but also reveal unforseen outcomes—the indirect effect on females—when natural selection targets sex-limited sexually selected characters.
Abstract.
Richardson S, Lintott P, Hosken D, Economou T, Matthews F (2021). Peaks in bat activity at turbines and the implications for mitigating the impact of wind energy developments on bats. Scientific Reports, 11
House CM, Lewis Z, Sharma MD, Hodgson DJ, Hunt J, Wedell N, Hosken DJ (2021). Sexual selection on the genital lobes of male Drosophila simulans.
Evolution,
75(2), 501-514.
Abstract:
Sexual selection on the genital lobes of male Drosophila simulans.
Sexual selection is thought to be responsible for the rapid divergent evolution of male genitalia with several studies detecting multivariate sexual selection on genital form. However, in most cases, selection is only estimated during a single episode of selection, which provides an incomplete view of net selection on genital traits. Here, we estimate the strength and form of multivariate selection on the genitalia arch of Drosophila simulans when mating occurs in the absence of a competitor and during sperm competition, in both sperm defence and offense roles (i.e. when mating first and last). We found that the strength of sexual selection on the genital arch was strongest during noncompetitive mating and weakest during sperm offense. However, the direction of selection was similar across selection episodes with no evidence for antagonistic selection. Overall, selection was not particularly strong despite genitals clearly evolving rapidly in this species.
Abstract.
Author URL.
2020
Singh KS, Hosken DJ, Wedell N, Ffrench-Constant R, Bass C, Baxter S, Paszkiewicz K, Sharma MD (2020). De Novo Genome Assembly of the Meadow Brown Butterfly, Maniola jurtina.
G3 (Bethesda),
10(5), 1477-1484.
Abstract:
De Novo Genome Assembly of the Meadow Brown Butterfly, Maniola jurtina.
Meadow brown butterflies (Maniola jurtina) on the Isles of Scilly represent an ideal model in which to dissect the links between genotype, phenotype and long-term patterns of selection in the wild - a largely unfulfilled but fundamental aim of modern biology. To meet this aim, a clear description of genotype is required. Here we present the draft genome sequence of M. jurtina to serve as a founding genetic resource for this species. Seven libraries were constructed using pooled DNA from five wild caught spotted females and sequenced using Illumina, PacBio RSII and MinION technology. A novel hybrid assembly approach was employed to generate a final assembly with an N50 of 214 kb (longest scaffold 2.9 Mb). The sequence assembly described here predicts a gene count of 36,294 and includes variants and gene duplicates from five genotypes. Core BUSCO (Benchmarking Universal Single-Copy Orthologs) gene sets of Arthropoda and Insecta recovered 90.5% and 88.7% complete and single-copy genes respectively. Comparisons with 17 other Lepidopteran species placed 86.5% of the assembled genes in orthogroups. Our results provide the first high-quality draft genome and annotation of the butterfly M. jurtina.
Abstract.
Author URL.
Simmons LW, Parker GA, Hosken DJ (2020). Evolutionary insight from a humble fly: Sperm competition and the yellow dungfly.
Philosophical Transactions of the Royal Society B: Biological Sciences,
375(1813).
Abstract:
Evolutionary insight from a humble fly: Sperm competition and the yellow dungfly
Studies of the yellow dungfly in the 1960s provided one of the first quantitative demonstrations of the costs and benefits associated with male and female reproductive behaviour. These studies advanced appreciation of sexual selection as a significant evolutionary mechanism and contributed to the 1970s paradigm shift toward individual selectionist thinking. Three behaviours in particular led to the realization that sexual selection can continue during and after mating: (i) female receptivity to remating, (ii) sperm displacement and (iii) post-copulatory mate guarding. These behaviours either generate, or are adaptations to sperm competition, cryptic female choice and sexual conflict. Here we review this body of work, and its contribution to the development of post-copulatory sexual selection theory. This article is part of the theme issue 'Fifty years of sperm competition'.
Abstract.
Matsumura K, Abe MS, Sharma MD, Hosken DJ, Yoshii T, Miyatake T (2020). Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae).
Biological Journal of the Linnean Society,
130(1), 34-40.
Abstract:
Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae)
Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effects are rarely investigated. Here, we used 18 isofemale lines (genotypes) of Gnatocerus cornutus to assess rhythms of locomotor activity, while also testing for temperature effects. We found that total activity and the power of the circadian rhythm were affected by interactions between sex and genotype or between sex, genotype and temperature. The males tended to be more active and showed greater increases in activity, but this effect varied across both genotypes and temperatures. The period of activity varied only by genotype and was thus independent of temperature. The complicated genotype-sex-environment interactions we recorded stress the importance of investigating circadian activity in more integrated ways.
Abstract.
Theobald E, Hosken DJ, Foster P, Moyes K (2020). Mines and bats: the impact of open-pit mining on bat activity.
ACTA CHIROPTEROLOGICA,
22(1), 157-166.
Author URL.
Okada K, Katsuki M, Sharma MD, Kiyose K, Seko T, Okada Y, Wilson AJ, Hosken DJ (2020). Natural selection reverses the exaggeration of a male sexually selected trait, which increases female fitness.
Archer CR, Carey MR, Noda T, Store SJ, Hosken DJ (2020). Offspring sex ratios are stable across the life course in Drosophila simulans.
J Evol Biol,
33(11), 1606-1613.
Abstract:
Offspring sex ratios are stable across the life course in Drosophila simulans.
Within populations, adult sex ratios influence population growth and extinction risk, mating behaviours and parental care. Sex ratio adjustment can also have pronounced effects on individual fitness. Accordingly, it is important that we understand how often, and why, offspring sex ratios deviate from parity. In Drosophila melanogaster, females appear to improve their fitness by producing fewer sons when paired with older males. However, facultative sex ratio adjustment in D. melanogaster is controversial, and our understanding of how sex ratio skew affects fitness is hampered by pronounced sexual conflict in this species. Additionally, it is unclear whether maternal age or quality interacts with paternal age to influence offspring sex ratios. Here, we test whether offspring sex ratios vary as a function of maternal quality, and maternal and paternal age in Drosophila simulans, a sister species of D. melanogaster that lacks overt sexual conflict. We find that offspring sex ratios are slightly male-biased overall, but constant across the female life course, and independent of female quality, or paternal age. To really understand if, how and when females skew offspring sex ratios, we need studies linking offspring sex ratios to paternal and maternal phenotypes that are predicted to shift optimal investment in sons and daughters.
Abstract.
Author URL.
2019
Richardson SM, Lintott PR, Hosken DJ, Mathews F (2019). An evidence-based approach to specifying survey effort in ecological assessments of bat activity.
Biological Conservation,
231, 98-102.
Abstract:
An evidence-based approach to specifying survey effort in ecological assessments of bat activity
Robust ecological assessments are fundamental for effective wildlife conservation. Owing to the high legal protection of bats, surveys are frequently required as part of ecological assessments. Yet there is uncertainty about the amount of survey effort that should be deployed to facilitate bat protection. Bat activity can be extremely variable, and capturing periods of high activity can be as important as estimating parameters such as the median activity level. However the frequency and intensity of surveys required to capture the required information is unknown. Here we assessed the probability that acoustic surveys of differing durations would detect periods of high activity within a focal site and the importance of a site relative to others in a regional or national context. We randomly subsampled from 660 nights of activity data collected from 33 wind farm sites across Britain. The minimum surveying effort required to classify bat activity accurately varied between species and was dependent on weather conditions. We found that the survey periods required to give reasonable certainty in assessing risk exceeded those currently recommended in Europe. The approach of using bat activity accumulation curves, as described here, is transferrable to other situations where determining surveying effort and risk is necessary to ensure that ecological assessments provide a robust evidence base, whilst minimising the time and expense of surveys.
Abstract.
Matsumura K, Archer CR, Hosken DJ, Miyatake T (2019). Artificial selection on walking distance suggests a mobility-sperm competitiveness trade-off.
Behavioral Ecology,
30(6), 1522-1529.
Abstract:
Artificial selection on walking distance suggests a mobility-sperm competitiveness trade-off
AbstractSecuring matings is a key determinant of fitness, and in many species, males are the sex that engages in mate searching. Searching for mates is often associated with increased mobility. This elevated investment in movement is predicted to trade-off with sperm competitiveness, but few studies have directly tested whether this trade-off occurs. Here, we assessed whether artificial selection on mobility affected sperm competitiveness and mating behavior, and if increased mobility was due to increased leg length in red flour beetles (Tribolium castaneum). We found that, in general, males selected for decreased mobility copulated for longer, stimulated females more during mating, and tended to be better sperm competitors. Surprisingly, they also had longer legs. However, how well males performed in sperm competition depended on females. Males with reduced mobility always copulated for longer than males with high mobility, but this only translated into greater fertilization success in females from control populations and not the selection populations (i.e. treatment females). These results are consistent with a mate-searching/mating-duration trade-off and broadly support a trade-off between mobility and sperm competitiveness.
Abstract.
Tourmente M, Archer CR, Hosken DJ (2019). Complex interactions between sperm viability and female fertility.
Sci Rep,
9(1).
Abstract:
Complex interactions between sperm viability and female fertility.
Sperm viability is a major male fitness component, with higher sperm viability associated with enhanced sperm competitiveness. While many studies have focussed on sperm viability from the male fitness standpoint, its impact on female fitness is less clear. Here we used a panel of 32 isogenic Drosophila simulans lines to test for genetic variation in sperm viability (percentage of viable cells). We then tested whether sperm viability affected female fitness by mating females to males from low or high sperm viability genotypes. We found significant variation in sperm viability among genotypes, and consistent with this, sperm viability was highly repeatable within genotypes. Additionally, females mated to high sperm viability males laid more eggs in the first seven hours after mating, and produced more offspring in total. However, the early increase in oviposition did not result in more offspring in the 8 hours following mating, suggesting that mating with high sperm-viability genotypes leads to egg wastage for females shortly after copulation. Although mating with high sperm-viability males resulted in higher female fitness in the long term, high quality ejaculates would result in a short-term female fitness penalty, or at least lower realised fitness, potentially generating sexual conflict over optimal sperm viability.
Abstract.
Author URL.
Okada K, Okada Y, Dall SRX, Hosken DJ (2019). Loser-effect duration evolves independently of fighting ability. Proceedings of the Royal Society B: Biological Sciences, 286(1903), 20190582-20190582.
House CM, Rapkin J, Hunt J, Hosken DJ (2019). Operational sex ratio and density predict the potential for sexual selection in the broad-horned beetle.
Animal Behaviour,
152, 63-69.
Abstract:
Operational sex ratio and density predict the potential for sexual selection in the broad-horned beetle
Sexual selection can act on all aspects of the phenotype and the opportunity for selection (Is) sets its maximal strength. Popular approaches to alter is include the manipulation of the operational sex ratio (OSR) and/or density, with an increase in is predicted with a male-biased OSR and at higher density. However, debate continues regarding the utility of is to measure meaningful changes in the strength of selection, as changes in is with OSR and density may only reflect stochastic processes. Here we tested whether the manipulation of OSR and density alters is in the broad-horned flour beetle, Gnatocerus cornutus, a species where males are under intense sexual selection and the targets of selection are known. We also recorded the average number of fights and mating behaviour of individuals in our competitive arenas. We found significant main effects of OSR and density on is, with the opportunity for selection being highest in male-biased high-density treatments. There were also significant effects of OSR and density on the average number of matings, whereas only density influenced the average number of fights. These results suggest that manipulation of OSR and density influence the opportunity for sexual selection in G. cornutus and our observations of fighting and mating behaviour provide a proximate mechanism for the change in is.
Abstract.
Hosken DJ, Archer CR, Mank JE (2019). Sexual conflict.
Current Biology,
29(11), R451-R455.
Abstract:
Sexual conflict
Evolutionary conflict arises from differences in the fitness interests of replicating entities and has its roots in relatedness asymmetries. Every replicator is related to itself by 100%, but in most cases is less related to other replicators, which generates selfishness and conflicts of interest. Since this basic condition is the norm at many levels of biological organization, conflict is rife in biological systems. Sexual conflict, on which we focus here, is the evolutionary conflict that occurs between males and females because of their divergent fitness interests. Sexual conflict occurs despite sexual reproduction requiring some level of cooperation between males and females because the fitness interests of the sexes are nevertheless never perfectly aligned. In other words, males and females may agree on where they are going, but not necessarily on how to get there. Sexual conflict is a vast topic with relevance to many areas of biology and so here we restrict our focus to matters we think are of broadest interest. Hosken et al. introduce sexual conflict.
Abstract.
Hawkes MF, Duffy E, Joag R, Skeats A, Radwan J, Wedell N, Sharma MD, Hosken DJ, Troscianko J (2019). Sexual selection drives the evolution of male wing interference patterns.
Proc Biol Sci,
286(1903).
Abstract:
Sexual selection drives the evolution of male wing interference patterns.
The seemingly transparent wings of many insects have recently been found to display unexpected structural coloration. These structural colours (wing interference patterns: WIPs) may be involved in species recognition and mate choice, yet little is known about the evolutionary processes that shape them. Furthermore, to date investigations of WIPs have not fully considered how they are actually perceived by the viewers' colour vision. Here, we use multispectral digital imaging and a model of Drosophila vision to compare WIPs of male and female Drosophila simulans from replicate populations forced to evolve with or without sexual selection for 68 generations. We show that WIPs modelled in Drosophila vision evolve in response to sexual selection and provide evidence that WIPs correlate with male sexual attractiveness. These findings add a new element to the otherwise well-described Drosophila courtship display and confirm that wing colours evolve through sexual selection.
Abstract.
Author URL.
Hosken DJ, Wilson A (2019). The problem of measuring trait-preference correlations without disrupting them. Behavioral Ecology, 30(6), 1518-1521.
Duffy E, Archer CR, Sharma MD, Prus M, Joag RA, Radwan J, Wedell N, Hosken DJ (2019). Wolbachia infection can bias estimates of intralocus sexual conflict.
Ecology and Evolution,
9(1), 328-338.
Abstract:
Wolbachia infection can bias estimates of intralocus sexual conflict
Males and females share most of their genome and develop many of the same traits. However, each sex frequently has different optimal values for these shared traits, creating intralocus sexual conflict. This conflict has been observed in wild and laboratory populations of insects and affects important evolutionary processes such as sexual selection, the maintenance of genetic variation, and possibly even speciation. Given the broad impacts of intralocus conflict, accurately detecting and measuring it is important. A common way to detect intralocus sexual conflict is to calculate the intersexual genetic correlation for fitness, with negative values suggesting conflict. Here, we highlight a potential confounder of this measure—cytoplasmic incompatibility caused by the intracellular parasite Wolbachia. Infection with Wolbachia can generate negative intersexual genetic correlations for fitness in insects, suggestive of intralocus sexual conflict. This is because cytoplasmic incompatibility reduces the fitness of uninfected females mated to infected males, while uninfected males will not suffer reductions in fitness if they mate with infected females and may even be fitter than infected males. This can lead to strong negative intersexual genetic correlations for fitness, mimicking intralocus conflict. We illustrate this issue using simulations and then present Drosophila simulans data that show how reproductive incompatibilities caused by Wolbachia infection can generate signals of intralocus sexual conflict. Given that Wolbachia infection in insect populations is pervasive, but populations usually contain both infected and uninfected individuals providing scope for cytoplasmic incompatibility, this is an important consideration for sexual conflict research but one which, to date, has been largely underappreciated.
Abstract.
2018
Hosken DJ, Hodgson D, Buss D (2018). Beware the F-test (or, how to compare variances). Animal Behaviour, 136, 119-126.
Hosken DJ, Archer R, House C, Wedell N (2018). Penis evolution across species: divergence and diversity. Nature Reviews Urology
Hosken DJ, Sutter A, Barton S, Dev M, Basellini U, Archer R (2018). Senescent declines in elite tennis players are similar across the sexes. Behavioral Ecology
2017
Maraqa MS, Griffin R, Sharma MD, Wilson AJ, Hunt J, Hosken DJ, House CM (2017). Constrained evolution of the sex comb in Drosophila simulans.
J Evol Biol,
30(2), 388-400.
Abstract:
Constrained evolution of the sex comb in Drosophila simulans.
Male fitness is dependent on sexual traits that influence mate acquisition (precopulatory sexual selection) and paternity (post-copulatory sexual selection), and although many studies have documented the form of selection in one or the other of these arenas, fewer have done it for both. Nonetheless, it appears that the dominant form of sexual selection is directional, although theoretically, populations should converge on peaks in the fitness surface, where selection is stabilizing. Many factors, however, can prevent populations from reaching adaptive peaks. Genetic constraints can be important if they prevent the development of highest fitness phenotypes, as can the direction of selection if it reverses across episodes of selection. In this study, we examine the evidence that these processes influence the evolution of the multivariate sex comb morphology of male Drosophila simulans. To do this, we conduct a quantitative genetic study together with a multivariate selection analysis to infer how the genetic architecture and selection interact. We find abundant genetic variance and covariance in elements of the sex comb. However, there was little evidence for directional selection in either arena. Significant nonlinear selection was detected prior to copulation when males were mated to nonvirgin females, and post-copulation during sperm offence (again with males mated to nonvirgins). Thus, contrary to our predictions, the evolution of the D. simulans sex comb is limited neither by genetic constraints nor by antagonistic selection between pre- and post-copulatory arenas, but nonlinear selection on the multivariate phenotype may prevent sex combs from evolving to reach some fitness maximizing optima.
Abstract.
Author URL.
Baxter SW, Hoffman JI, Tregenza T, Wedell N, Hosken DJ (2017). EB Ford revisited: assessing the long-term stability of wing-spot patterns and population genetic structure of the meadow brown butterfly on the Isles of Scilly.
Heredity (Edinb),
118(4), 322-329.
Abstract:
EB Ford revisited: assessing the long-term stability of wing-spot patterns and population genetic structure of the meadow brown butterfly on the Isles of Scilly.
Understanding selection in the wild remains a major aim of evolutionary ecology and work by Ford and colleagues on the meadow brown butterfly Maniola jurtina did much to ignite this agenda. A great deal of their work was conducted during the 1950s on the Isles of Scilly. They documented island-specific wing-spot patterns that remained consistent over about a decade, but patterns on some islands changed after environmental perturbation. It was suggested that these wing-spot patterns reflected island-specific selection and that there was little migration between islands. However, genetic studies to test the underlying assumption of restricted migration are lacking and it is also unknown whether the originally described wing-spot patterns have persisted over time. We therefore collected female butterflies from five of Ford's original study locations, including three large islands (St Mary's, St Martin's and Tresco) and two small islands (Tean and St Helen's). Wing-spot patterns had not changed appreciably over time on three of the islands (two large and one small), but were significantly different on the other two. Furthermore, analysis of 176 amplified fragment length polymorphisms revealed significant genome-wide differentiation among the five islands. Our findings are consistent with Ford's conclusions that despite the close proximity of these islands, there is restricted gene flow among them.
Abstract.
Author URL.
Wedell N, Rostant W, Bowyer J, Coupland J, Facey J, Hosken DJ (2017). Pleiotropic effects of DDT resistance on male size and behaviour. Behavior Genetics, 47, 449-458.
Archer CR, Stephens RM, Sharma MD, Hosken DJ (2017). The Drosophila simulans Y chromosome interacts with the autosomes to influence male fitness.
J Evol Biol,
30(10), 1821-1825.
Abstract:
The Drosophila simulans Y chromosome interacts with the autosomes to influence male fitness.
The Y chromosome should degenerate because it cannot recombine. However, male-limited transmission increases selection efficiency for male-benefit alleles on the Y, and therefore, Y chromosomes should contribute significantly to variation in male fitness. This means that although the Drosophila Y chromosome is small and gene-poor, Y-linked genes are vital for male fertility in Drosophila melanogaster and the Y chromosome has large male fitness effects. It is unclear whether the same pattern is seen in the closely related Drosophila simulans. We backcrossed Y chromosomes from three geographic locations into five genetic backgrounds and found strong Y and genetic background effects on male fertility. There was a significant Y-background interaction, indicating substantial epistasis between the Y and autosomal genes affecting male fertility. This supports accumulating evidence that interactions between the Y chromosome and the autosomes are key determinants of male fitness.
Abstract.
Author URL.
Wedell N, Hosken DJ (2017). Three billion years of research
and development. NATURE ECOLOGY & EVOLUTION, 1
2016
Lintott PR, Richardson SM, Hosken DJ, Fensome SA, Mathews F (2016). Ecological impact assessments fail to reduce risk of bat casualties at wind farms.
Curr Biol,
26(21), R1135-R1136.
Abstract:
Ecological impact assessments fail to reduce risk of bat casualties at wind farms.
Demand for renewable energy is rising exponentially. While this has benefits in reducing greenhouse gas emissions, there may be costs to biodiversity [1]. Environmental Impact Assessments (EIAs) are the main tool used across the world to predict the overall positive and negative effects of renewable energy developments before planning consent is given, and the Ecological Impact Assessments (EcIAs) within them assess their species-specific effects. Given that EIAs are undertaken globally, are extremely expensive, and are enshrined in legislation, their place in evidence-based decision making deserves evaluation. Here we assess how well EIAs of wind-farm developments protect bats. We found they do not predict the risks to bats accurately, and even in those cases where high risk was correctly identified, the mitigation deployed did not avert the risk. Given that the primary purpose of an EIA is to make planning decisions evidence-based, our results indicate that EIA mitigation strategies used to date have been ineffective in protecting bats. In the future, greater emphasis should be placed on assessing the actual impacts post-construction and on developing effective mitigation strategies.
Abstract.
Author URL.
Archer CR, Hosken DJ (2016). Evolution: Escaping the Inevitability of Ageing.
Current Biology,
26(5), R202-R204.
Abstract:
Evolution: Escaping the Inevitability of Ageing
William Hamilton argued that even species inhabiting the farthest flung corners of the universe should age. However, a recent study shows that to find a species that escapes ageing, you only need to look as far as your local pond.
Abstract.
Perry JC, Joag R, Hosken DJ, Wedell N, Radwan J, Wigby S (2016). Experimental evolution under hyper-promiscuity in Drosophila melanogaster.
BMC Evol Biol,
16(1).
Abstract:
Experimental evolution under hyper-promiscuity in Drosophila melanogaster.
BACKGROUND: the number of partners that individuals mate with over their lifetime is a defining feature of mating systems, and variation in mate number is thought to be a major driver of sexual evolution. Although previous research has investigated the evolutionary consequences of reductions in the number of mates, we know little about the costs and benefits of increased numbers of mates. Here, we use a genetic manipulation of mating frequency in Drosophila melanogaster to create a novel, highly promiscuous mating system. We generated D. melanogaster populations in which flies were deficient for the sex peptide receptor (SPR) gene - resulting in SPR- females that mated more frequently - and genetically-matched control populations, and allowed them to evolve for 55 generations. At several time-points during this experimental evolution, we assayed behavioural, morphological and transcriptional reproductive phenotypes expected to evolve in response to increased population mating frequencies. RESULTS: We found that males from the high mating frequency SPR- populations evolved decreased ability to inhibit the receptivity of their mates and decreased copulation duration, in line with predictions of decreased per-mating investment with increased sperm competition. Unexpectedly, SPR- population males also evolved weakly increased sex peptide (SP) gene expression. Males from SPR- populations initially (i.e. before experimental evolution) exhibited more frequent courtship and faster time until mating relative to controls, but over evolutionary time these differences diminished or reversed. CONCLUSIONS: in response to experimentally increased mating frequency, SPR- males evolved behavioural responses consistent with decreased male post-copulatory investment at each mating and decreased overall pre-copulatory performance. The trend towards increased SP gene expression might plausibly relate to functional differences in the two domains of the SP protein. Our study highlights the utility of genetic manipulations of animal social and sexual environments coupled with experimental evolution.
Abstract.
Author URL.
Sharma MD, Wilson AJ, Hosken DJ (2016). Fisher's sons' effect in sexual selection: absent, intermittent or just low experimental power?.
J Evol Biol,
29(12), 2464-2470.
Abstract:
Fisher's sons' effect in sexual selection: absent, intermittent or just low experimental power?
The Fisherian sexual selection paradigm has been called the null model of sexual selection. At its heart is the expectation of a genetic correlation (rG ) between female preference and male trait. However, recent meta-analysis has shown estimated correlations are often extremely weak and not statistically significant. We show here that systematic failure of studies to reject the null hypothesis that rG = 0 is almost certainly due to the low power of most experimental designs used. We provide an easy way to assess experimental power a priori and suggest that current data make it difficult to definitively test a key component of the Fisher effect.
Abstract.
Author URL.
Hawkes MF, Gamble CE, Turner ECR, Carey MR, Wedell N, Hosken DJ (2016). Intralocus sexual conflict and insecticide resistance.
Proceedings of the Royal Society B: Biological Sciences,
283(1843).
Abstract:
Intralocus sexual conflict and insecticide resistance
The BA allele of the Drosophila cytochrome P450 gene Cyp6g1 confers resistance to a range of insecticides. It is also subject to intralocus sexual conflict when introgressed into the Canton-S background, whose collection predates the widespread use of insecticides. In this genetic background, the allele confers a pleiotropic fitness benefit to females but a cost to males, and exhibits little sexual dimorphism in conferred insecticide resistance. It is unclear whether these sexually antagonistic effects also exist in current populations that have naturally evolved with insecticides, where genetic modifiers that offset male costs might be expected to evolve. Here, we explore these issues using Drosophila melanogaster caught recently from an Australian population in which the BA allele naturally segregates. While we find increased fecundity in insecticide-resistant BA females and no consistent evidence of fitness costs in males, experimental evolution indicates balancing selection at the locus. We suggest that this apparent discrepancy may be due to reduced investment in reproduction in resistant males. Our results at the population level are consistent with previous work, and suggest that individual-level fitness assays do not always capture sexually antagonistic fitness effects that emerge in a population context.
Abstract.
House CM, Jensen K, Rapkin J, Lane S, Okada K, Hosken DJ, Hunt J (2016). Macronutrient balance mediates the growth of sexually selected weapons but not genitalia in male broad-horned beetles.
Functional Ecology,
30(5), 769-779.
Abstract:
Macronutrient balance mediates the growth of sexually selected weapons but not genitalia in male broad-horned beetles
Condition is defined as the pool of resources available to an individual that can be allocated to fitness-enhancing traits. Consequently, condition could influence developmental trade-offs if any occur. Although many studies have manipulated diet to demonstrate condition-dependent trait expression, few studies have determined the contribution of specific nutrients to condition or trade-offs. We used nutritional geometry to quantify the effects of dietary protein and carbohydrate content on larval performance and the development of adult morphology including body size as well as a primary and secondary sexually selected trait in male broad-horned beetles, Gnatocerus cornutus. We found that offspring survival, development rate and morphological traits were highly affected by dietary carbohydrate content and to a lesser extent by protein content and that all traits were maximized at a protein-to-carbohydrate ratio around 1:2. The absolute size of a secondary sexual character, the mandibles, had a heightened response to the increased availability and ratio of both macronutrients. Male genitalia, in contrast, were relatively insensitive to the increased availability of macronutrients. Overall, while nutrition influenced trait expression, the nutritional requirements of development rate and morphological traits were largely the same and resource acquisition seems to implement only weak trade-offs in this species. This finding contrasts with some resource constraint predictions, as beetles seem able to simultaneously meet the nutritional requirements of most traits.
Abstract.
Campbell AL, Levitan DR, Hosken DJ, Lewis C (2016). Ocean acidification changes the male fitness landscape.
Sci Rep,
6Abstract:
Ocean acidification changes the male fitness landscape.
Sperm competition is extremely common in many ecologically important marine taxa. Ocean acidification (OA) is driving rapid changes to the marine environments in which freely spawned sperm operate, yet the consequences of OA on sperm performance are poorly understood in the context of sperm competition. Here, we investigated the impacts of OA (+1000 μatm pCO2) on sperm competitiveness for the sea urchin Paracentrotus lividus. Males with faster sperm had greater competitive fertilisation success in both seawater conditions. Similarly, males with more motile sperm had greater sperm competitiveness, but only under current pCO2 levels. Under OA the strength of this association was significantly reduced and there were male sperm performance rank changes under OA, such that the best males in current conditions are not necessarily best under OA. Therefore OA will likely change the male fitness landscape, providing a mechanism by which environmental change alters the genetic landscape of marine species.
Abstract.
Author URL.
Archer CR, Hosken DJ (2016). Peacock flies.
Current Biology,
26(21), R1124-R1126.
Abstract:
Peacock flies
A quick guide on peacock flies, a species of insect where, unusually, both males and females perform dances apparently to attract mates.
Abstract.
House CM, Sharma MD, Okada K, Hosken DJ (2016). Pre and Post-copulatory Selection Favor Similar Genital Phenotypes in the Male Broad Horned Beetle.
Integr Comp Biol,
56(4), 682-693.
Abstract:
Pre and Post-copulatory Selection Favor Similar Genital Phenotypes in the Male Broad Horned Beetle.
Sexual selection can operate before and after copulation and the same or different trait(s) can be targeted during these episodes of selection. The direction and form of sexual selection imposed on characters prior to mating has been relatively well described, but the same is not true after copulation. In general, when male-male competition and female choice favor the same traits then there is the expectation of reinforcing selection on male sexual traits that improve competitiveness before and after copulation. However, when male-male competition overrides pre-copulatory choice then the opposite could be true. With respect to studies of selection on genitalia there is good evidence that male genital morphology influences mating and fertilization success. However, whether genital morphology affects reproductive success in more than one context (i.e. mating versus fertilization success) is largely unknown. Here we use multivariate analysis to estimate linear and nonlinear selection on male body size and genital morphology in the flour beetle Gnatocerus cornutus, simulated in a non-competitive (i.e. monogamous) setting. This analysis estimates the form of selection on multiple traits and typically, linear (directional) selection is easiest to detect, while nonlinear selection is more complex and can be stabilizing, disruptive, or correlational. We find that mating generates stabilizing selection on male body size and genitalia, and fertilization causes a blend of directional and stabilizing selection. Differences in the form of selection across these bouts of selection result from a significant alteration of nonlinear selection on body size and a marginally significant difference in nonlinear selection on a component of genital shape. This suggests that both bouts of selection favor similar genital phenotypes, whereas the strong stabilizing selection imposed on male body size during mate acquisition is weak during fertilization.
Abstract.
Author URL.
Hosken DJ, Alonzo SH, Wedell N (2016). Why aren’t signals of female quality more common?. Animal Behaviour, 114, 199-201.
2015
Brown AR, Owen SF, Peters J, Zhang Y, Soffker M, Paull GC, Hosken DJ, Wahab MA, Tyler CR (2015). Climate change and pollution speed declines in zebrafish populations.
Proc Natl Acad Sci U S A,
112(11), E1237-E1246.
Abstract:
Climate change and pollution speed declines in zebrafish populations.
Endocrine disrupting chemicals (EDCs) are potent environmental contaminants, and their effects on wildlife populations could be exacerbated by climate change, especially in species with environmental sex determination. Endangered species may be particularly at risk because inbreeding depression and stochastic fluctuations in male and female numbers are often observed in the small populations that typify these taxa. Here, we assessed the interactive effects of water temperature and EDC exposure on sexual development and population viability of inbred and outbred zebrafish (Danio rerio). Water temperatures adopted were 28 °C (current ambient mean spawning temperature) and 33 °C (projected for the year 2100). The EDC selected was clotrimazole (at 2 μg/L and 10 μg/L), a widely used antifungal chemical that inhibits a key steroidogenic enzyme [cytochrome P450(CYP19) aromatase] required for estrogen synthesis in vertebrates. Elevated water temperature and clotrimazole exposure independently induced male-skewed sex ratios, and the effects of clotrimazole were greater at the higher temperature. Male sex ratio skews also occurred for the lower clotrimazole exposure concentration at the higher water temperature in inbred fish but not in outbred fish. Population viability analysis showed that population growth rates declined sharply in response to male skews and declines for inbred populations occurred at lower male skews than for outbred populations. These results indicate that elevated temperature associated with climate change can amplify the effects of EDCs and these effects are likely to be most acute in small, inbred populations exhibiting environmental sex determination and/or differentiation.
Abstract.
Author URL.
Okada K, Archer CR, Katsuki M, Suzaki Y, Sharma MD, House CM, Hosken DJ (2015). Polyandry and fitness in female horned flour beetles, Gnatocerus cornutus.
Animal Behaviour,
106, 11-16.
Abstract:
Polyandry and fitness in female horned flour beetles, Gnatocerus cornutus
Although polyandry is common, it is often unclear why females mate with multiple males, because although polyandry may provide females with direct or indirect fitness benefits, it can also be costly. Our understanding of polyandry is also restricted by the relative paucity of studies that disentangle the fitness effects of mating more than once with a single male and mating with multiple males. Here we investigated potential benefits and costs of polyandry in the horned beetle, Gnatocerus cornutus, while controlling for the number of matings. We found that female life span was independent of mating frequency, indicating that mating itself is not very costly. However, females that mated more than once laid more eggs and had greater lifetime reproductive success than singly mated females. Because the magnitude of these effects was similar in monandrous and polyandrous females, this improved fertility was due to multiple mating itself, rather than mating with multiple males. However, although polyandrous females produced more attractive sons, these males tended to have smaller mandibles and so may fare less well in male-male competition. The se results indicate that polyandry is relatively cost free, at least in the laboratory, and has direct and indirect benefits to female fitness. However, because the attractive sons produced by polyandrous females may fight less well, the indirect benefits of polyandry will depend on the intensity of male-male competition and how free females are to exert mate choice. Where competition between males is intense, polyandry benefits via son attractiveness may be reduced and perhaps even carry costs to female fitness.
Abstract.
Moussy C, Atterby H, Griffiths AGF, Allnutt TR, Mathews F, Smith GC, Aegerter JN, Bearhop S, Hosken DJ (2015). Population genetic structure of serotine bats (Eptesicus serotinus) across Europe and implications for the potential spread of bat rabies (European bat lyssavirus EBLV-1).
Heredity (Edinb),
115(1), 83-92.
Abstract:
Population genetic structure of serotine bats (Eptesicus serotinus) across Europe and implications for the potential spread of bat rabies (European bat lyssavirus EBLV-1).
Understanding of the movements of species at multiple scales is essential to appreciate patterns of population connectivity and in some cases, the potential for pathogen transmission. The serotine bat (Eptesicus serotinus) is a common and widely distributed species in Europe where it frequently harbours European bat lyssavirus type 1 (EBLV-1), a virus causing rabies and transmissible to humans. In the United Kingdom, it is rare, with a distribution restricted to south of the country and so far the virus has never been found there. We investigated the genetic structure and gene flow of E. serotinus across the England and continental Europe. Greater genetic structuring was found in England compared with continental Europe. Nuclear data suggest a single population on the continent, although further work with more intensive sampling is required to confirm this, while mitochondrial sequences indicate an east-west substructure. In contrast, three distinct populations were found in England using microsatellite markers, and mitochondrial diversity was very low. Evidence of nuclear admixture indicated strong male-mediated gene flow among populations. Differences in connectivity could contribute to the high viral prevalence on the continent in contrast with the United Kingdom. Although the English Channel was previously thought to restrict gene flow, our data indicate relatively frequent movement from the continent to England highlighting the potential for movement of EBLV-1 into the United Kingdom.
Abstract.
Author URL.
Hodgson D, McDonald JL, Hosken DJ (2015). Resilience is Complicated, but Comparable: a Reply to Yeung and Richardson. Trends in Ecology and Evolution
Archer CR, Duffy E, Hosken DJ, Mokkonen M, Okada K, Oku K, Sharma MD, Hunt J (2015). Sex-specific effects of natural and sexual selection on the evolution of life span and ageing in Drosophila simulans.
Functional Ecology,
29(4), 562-569.
Abstract:
Sex-specific effects of natural and sexual selection on the evolution of life span and ageing in Drosophila simulans
Variation in the strength of age-dependent natural selection shapes differences in ageing rates across species and populations. Likewise, sexual selection can promote divergent patterns of senescence across the sexes. However, the effects of these processes on the evolution of ageing have largely been considered independently, and interactions between them are poorly understood. We use experimental evolution to investigate how natural and sexual selection affect life span and ageing in Drosophila simulans. Replicate populations were evolved under lifetime monogamy (relaxed sexual selection) or lifetime polyandry (elevated sexual selection) and at one of two temperatures, 25 °C (relaxed natural selection) or 27 °C (enhanced natural selection), in a fully factorial design. We measured longevity in 150 individually housed flies taken from each of three replicate populations per selection regime. We found that natural and sexual selection affected the evolution of life span via sex-specific effects on different ageing parameters (ageing rate vs. baseline mortality): natural selection reduced the rate of ageing in both sexes but increased male baseline mortality, while sexual selection elevated baseline mortality in both sexes but particularly in males. This means that sexual and natural selection interacted to reduce male life span but acted on female life span by independently affecting particular ageing parameters. Sex-specific effects of sexual and natural selection may help explain the diverse patterns of ageing seen in nature but complicate predictions about how ageing and life span evolve across the sexes.
Abstract.
Rostant WG, Kay C, Wedell N, Hosken DJ (2015). Sexual conflict maintains variation at an insecticide resistance locus.
BMC Biol,
13Abstract:
Sexual conflict maintains variation at an insecticide resistance locus.
BACKGROUND: the maintenance of genetic variation through sexually antagonistic selection is controversial, partly because specific sexually-antagonistic alleles have not been identified. The Drosophila DDT resistance allele (DDT-R) is an exception. This allele increases female fitness, but simultaneously decreases male fitness, and it has been suggested that this sexual antagonism could explain why polymorphism was maintained at the locus prior to DDT use. We tested this possibility using a genetic model and then used evolving fly populations to test model predictions. RESULTS: Theory predicted that sexual antagonism is able to maintain genetic variation at this locus, hence explaining why DDT-R did not fix prior to DDT use despite increasing female fitness, and experimentally evolving fly populations verified theoretical predictions. CONCLUSIONS: This demonstrates that sexually antagonistic selection can maintain genetic variation and explains the DDT-R frequencies observed in nature.
Abstract.
Author URL.
Hodgson D, McDonald JL, Hosken DJ (2015). What do you mean, 'resilient'?.
Trends in Ecology and EvolutionAbstract:
What do you mean, 'resilient'?
In a world beset by environmental disasters and anthropogenic disturbances, resilience might be the key to the persistence of natural systems. Yet, the 'measurement' of resilience is hampered by the multiple (and often conflicting) processes that yield the response of systems to insult. We recommend the simultaneous consideration of 'resistance' and 'recovery' as measurable components that together represent resilience.
Abstract.
2014
Hosken DJ, Hunt J (2014). Conclusions and Final Thoughts. In (Ed) Genotype-by-Environment Interactions and Sexual Selection, 331-334.
Mank JE, Hosken DJ, Wedell N (2014). Conflict on the sex chromosomes: cause, effect, and complexity.
Cold Spring Harb Perspect Biol,
6(12).
Abstract:
Conflict on the sex chromosomes: cause, effect, and complexity.
Intralocus sexual conflict and intragenomic conflict both affect sex chromosome evolution and can in extreme cases even cause the complete turnover of sex chromosomes. Additionally, established sex chromosomes often become the focus of heightened conflict. This creates a tangled relationship between sex chromosomes and conflict with respect to cause and effect. To further complicate matters, sexual and intragenomic conflict may exacerbate one another and thereby further fuel sex chromosome change. Different magnitudes and foci of conflict offer potential explanations for lineage-specific variation in sex chromosome evolution and answer long-standing questions as to why some sex chromosomes are remarkably stable, whereas others show rapid rates of evolutionary change.
Abstract.
Author URL.
Ingleby FC, Hosken DJ, Flowers K, Hawkes MF, Lane SM, Rapkin J, House CM, Sharma MD, Hunt J (2014). Environmental heterogeneity, multivariate sexual selection and genetic constraints on cuticular hydrocarbons in Drosophila simulans.
Journal of Evolutionary Biology,
27(4), 700-713.
Abstract:
Environmental heterogeneity, multivariate sexual selection and genetic constraints on cuticular hydrocarbons in Drosophila simulans
Sexual selection is responsible for the evolution of many elaborate traits, but sexual trait evolution could be influenced by opposing natural selection as well as genetic constraints. As such, the evolution of sexual traits could depend heavily on the environment if trait expression and attractiveness vary between environments. Here, male Drosophila simulans were reared across a range of diets and temperatures, and we examined differences between these environments in terms of (i) the expression of male cuticular hydrocarbons (CHCs) and (ii) which male CHC profiles were most attractive to females. Temperature had a strong effect on male CHC expression, whereas the effect of diet was weaker. Male CHCs were subject to complex patterns of directional, quadratic and correlational sexual selection, and we found differences between environments in the combination of male CHCs that were most attractive to females, with clearer differences between diets than between temperatures. We also show that genetic covariance between environments is likely to cause a constraint on independent CHC evolution between environments. Our results demonstrate that even across the narrow range of environmental variation studied here, predicting the outcome of sexual selection can be extremely complicated, suggesting that studies ignoring multiple traits or environments may provide an over-simplified view of the evolution of sexual traits. © 2014 European Society for Evolutionary Biology.
Abstract.
Hunt J, Hosken DJ (eds)(2014). Genotype-by-Environment Interactions and Sexual Selection. , Wiley Blackwell.
Duffy E, Joag R, Radwan J, Wedell N, Hosken DJ (2014). Inbreeding alters intersexual fitness correlations in Drosophila simulans.
ECOLOGY AND EVOLUTION,
4(17), 3330-3338.
Author URL.
Hosken DJ, Hunt J (2014). Preface.
Ingleby FC, Hosken DJ, Hunt J (2014). Sexual Selection and Genotype-by-Environment Interactions in Drosophila Cuticular Hydrocarbons. In (Ed)
Genotype-by-Environment Interactions and Sexual Selection, 265-281.
Abstract:
Sexual Selection and Genotype-by-Environment Interactions in Drosophila Cuticular Hydrocarbons
Abstract.
Edward DA, Stockley P, Hosken DJ (2014). Sexual conflict and sperm competition.
Cold Spring Harb Perspect Biol,
7(4).
Abstract:
Sexual conflict and sperm competition.
Traits that increase a male's fertilization success during sperm competition can be harmful to females and therefore represent a source of sexual conflict. In this review, we consider the variety of male adaptations to sperm competition (MASC) that may give rise to sexual conflict-including mate guarding, prolonged copulations, the transfer of large numbers of sperm, and the manipulation of females through nonsperm components of the ejaculate. We then reflect on the fitness economics influencing the escalation of these sexual conflicts, considering the likelihood of females evolving traits to offset the negative effects of MASC when compared with the strong selection on males that lead to MASC. We conclude by discussing the potential evolutionary outcomes of sexual conflict arising from MASC, including the opportunities for females to mitigate conflict costs and the prospects for conflict resolution.
Abstract.
Author URL.
Okada K, Katsuki M, Sharma MD, House CM, Hosken DJ (2014). Sexual conflict over mating in Gnatocerus cornutus? Females prefer lovers not fighters.
Proc Biol Sci,
281(1785).
Abstract:
Sexual conflict over mating in Gnatocerus cornutus? Females prefer lovers not fighters.
Female mate choice and male-male competition are the typical mechanisms of sexual selection. However, these two mechanisms do not always favour the same males. Furthermore, it has recently become clear that female choice can sometimes benefit males that reduce female fitness. So whether male-male competition and female choice favour the same or different males, and whether or not females benefit from mate choice, remain open questions. In the horned beetle, Gnatocerus cornutus, males have enlarged mandibles used to fight rivals, and larger mandibles provide a mating advantage when there is direct male-male competition for mates. However, it is not clear whether females prefer these highly competitive males. Here, we show that female choice targets male courtship rather than mandible size, and these two characters are not phenotypically or genetically correlated. Mating with attractive, highly courting males provided indirect benefits to females but only via the heritability of male attractiveness. However, mating with attractive males avoids the indirect costs to daughters that are generated by mating with competitive males. Our results suggest that male-male competition may constrain female mate choice, possibly reducing female fitness and generating sexual conflict over mating.
Abstract.
Author URL.
Hodgson DJ, Hosken DJ (2014). Ultimate and proximate functions of sperm RNA: a reply to Holman and Price.
Trends Ecol Evol,
29(12).
Author URL.
Hosken DJ, Hodgson DJ (2014). Why do sperm carry RNA? Relatedness, conflict, and control.
Trends Ecol Evol,
29(8), 451-455.
Abstract:
Why do sperm carry RNA? Relatedness, conflict, and control.
Classically, sperm were seen as transcriptionally inactive vehicles for delivering the paternal haplotype to an egg. Yet, it has become apparent that sperm also carry thousands of different RNAs, and the functions of most of these are unknown. Here, we make four novel suggestions for sperm RNA function. First, they could act as relatedness markers facilitating sperm cooperation. Second, they could act as paternally imposed suppressors of haploid interests. Third, they could act as a nuptial gift, providing the female with resources that entice her to fertilise ova using the sperm of the gift-provider. Fourth, they could represent the contents of a Trojan horse, delivered by males to manipulate female reproduction. We discuss these ideas and suggest how they might be tested.
Abstract.
Author URL.
2013
Mathews F, Swindells M, Goodhead R, August TA, Hardman P, Linton DM, Hosken DJ (2013). EFFECTIVENESS OF SEARCH DOGS COMPARED WITH HUMAN OBSERVERS IN LOCATING BAT CARCASSES AT WIND TURBINE SITES: a BLINDED RANDOMIZED TRIAL. Wildlife Society Bulletin, 37, 34-40.
Ingleby FC, Hunt J, Hosken DJ (2013). Genotype-by-Environment Interactions for Female Mate Choice of Male Cuticular Hydrocarbons in Drosophila simulans.
PLoS ONE,
8(6).
Abstract:
Genotype-by-Environment Interactions for Female Mate Choice of Male Cuticular Hydrocarbons in Drosophila simulans
Recent research has highlighted the potential importance of environmental and genotype-by-environment (G×E) variation in sexual selection, but most studies have focussed on the expression of male sexual traits. Consequently, our understanding of genetic variation for plasticity in female mate choice is extremely poor. In this study we examine the genetics of female mate choice in Drosophila simulans using isolines reared across two post-eclosion temperatures. There was evidence for G×Es in female choosiness and preference, which suggests that the evolution of female mate choice behaviour could differ across environments. However, the ranked order of preferred males was consistent across females and environments, so the same males are favoured by mate choice in spite of G×Es. Our study highlights the importance of taking cross-environment perspectives in order to gain a more comprehensive understanding of the operation of sexual selection. © 2013 Ingleby et al.
Abstract.
Ingleby FC, Hosken DJ, Flowers K, Hawkes MF, Lane SM, Rapkin J, Dworkin I, Hunt J (2013). Genotype-by-environment interactions for cuticular hydrocarbon expression in Drosophila simulans.
J Evol Biol,
26(1), 94-107.
Abstract:
Genotype-by-environment interactions for cuticular hydrocarbon expression in Drosophila simulans.
Genotype-by-environment interactions (G × Es) describe genetic variation for phenotypic plasticity. Recent interest in the role of these interactions in sexual selection has identified G × Es across a diverse range of species and sexual traits. Additionally, theoretical work predicts that G × Es in sexual traits could help to maintain genetic variation, but could also disrupt the reliability of these traits as signals of mate quality. However, empirical tests of these theoretical predictions are scarce. We reared iso-female lines of Drosophila simulans across two axes of environmental variation (diet and temperature) in a fully factorial design and tested for G × Es in the expression of cuticular hydrocarbons (CHCs), a multivariate sexual trait in this species. We find sex-specific environmental, genetic and G × E effects on CHC expression, with G × Es for diet in both male and female CHC profile and a G × E for temperature in females. We also find some evidence for ecological crossover in these G × Es, and by quantifying variance components, genetic correlations and heritabilities, we show the potential for these G × Es to help maintain genetic variation and cause sexual signal unreliability in D. simulans CHC profiles.
Abstract.
Author URL.
Ingleby FC, Hunt J, Hosken DJ (2013). Heritability of male attractiveness persists despite evidence for unreliable sexual signals in Drosophila simulans.
Journal of Evolutionary Biology,
26(2), 311-324.
Abstract:
Heritability of male attractiveness persists despite evidence for unreliable sexual signals in Drosophila simulans
Sexual signals can be used to attract mates, but to be honest indicators of signaller quality they need to convey information reliably. However, environmental variation and genotype-by-environment (G × E) interactions have the potential to compromise the reliability of sexual signals. Here, we test the reliability of cuticular hydrocarbons (CHCs) as signals of heritable aspects of male attractiveness in Drosophila simulans. We examined the heritability of male attractiveness and a measure of the difference between fathers' and sons' CHC profiles across dietary and temperature environments. Our results show that environmental heterogeneity disrupts the similarity of some components of father and son CHC profile. However, overall male attractiveness is heritable within and across environments, so that sire attractiveness is a good predictor of son attractiveness even with environmental heterogeneity. This suggests that although some male CHC signals are unreliable, attractive genotypes retain their attractiveness across environments on average. © 2012 European Society for Evolutionary Biology.
Abstract.
Ala-Honkola O, Hosken DJ, Manier MK, Lüpold S, Droge-Young EM, Berben KS, Collins WF, Belote JM, Pitnick S (2013). Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster.
Ecol Evol,
3(7), 2089-2102.
Abstract:
Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster.
Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e. fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer the mode of past selection on them. The use of transgenic populations of Drosophila melanogaster with red or green fluorescent-tagged sperm heads permitted in vivo discrimination of sperm from competing males and quantification of characteristics of ejaculate composition, performance, and fate. We found that male attractiveness (mating latency) and competitive fertilization success (P2) both show some inbreeding depression, suggesting they may have been under directional selection, whereas sperm length showed no inbreeding depression suggesting a history of stabilizing selection. However, despite having measured several sperm quality and quantity traits, our data did not allow us to discern the mechanism underlying the lowered competitive fertilization success of inbred (f = 0.50) males.
Abstract.
Author URL.
Bickley LK, Brown AR, Hosken DJ, Hamilton PB, Le Page G, Paull GC, Owen SF, Tyler CR (2013). Interactive effects of inbreeding and endocrine disruption on reproduction in a model laboratory fish.
Evolutionary Applications,
6(2), 279-289.
Abstract:
Interactive effects of inbreeding and endocrine disruption on reproduction in a model laboratory fish
Inbreeding depression is expected to be more severe in stressful environments. However, the extent to which inbreeding affects the vulnerability of populations to environmental stressors, such as chemical exposure, remains unresolved. Here we report on the combined impacts of inbreeding and exposure to an endocrine disrupting chemical (the fungicide clotrimazole) on zebrafish (Danio rerio). We show that whilst inbreeding can negatively affect reproductive traits, not all traits are affected equally. Inbreeding depression frequently only became apparent when fish were additionally stressed by chemical exposure. Embryo viability was significantly reduced in inbred exposed fish and there was a tendency for inbred males to sire fewer offspring when in direct competition with outbred individuals. Levels of plasma 11-ketotestosterone, a key male sex hormone, showed substantial inbreeding depression that was unaffected by addition of the fungicide. In contrast, there was no effect of inbreeding or clotrimazole exposure on egg production. Overall, our data provide evidence that stress may amplify the effects of inbreeding on key reproductive traits, particularly those associated with male fitness. This may have important implications when considering the consequences of exposure to chemical pollutants on the fitness of wild populations. Journal compilation © 2013 Blackwell Publishing Ltd62 February 2013 10.1111/j.1752-4571.2012.00288.x Original Article Original Articles © 2012 Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution Non Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Abstract.
Moussy C, Hosken DJ, Mathews F, Smith GC, Aegerter JN, Bearhop S (2013). Migration and dispersal patterns of bats and their influence on genetic structure. Mammal Review, 43, 183-195.
Sharma MD, Minder AM, Hosken DJ (2013). No association between sperm competition and sperm length variation across dung flies (Scathophagidae).
J Evol Biol,
26(11), 2341-2349.
Abstract:
No association between sperm competition and sperm length variation across dung flies (Scathophagidae).
Sperm length is extremely variable across species, but a general explanation for this variation is lacking. However, when the risk of sperm competition is high, sperm length is predicted to be less variable within species, and there is some evidence for this in birds and social insects. Here, we examined intraspecific variation in sperm length, both within and between males, and its potential associations with sperm competition risk and variation in female reproductive tract morphology across dung flies. We used two measures of variation in sperm size, and testis size was employed as our index of sperm competition risk. We found no evidence of associations between sperm length variation and sperm competition or female reproductive tract variation. These results suggest that variation in sperm competition risk may not always be associated with variation in sperm morphology, and the cause(s) of sperm length variation in dung flies remains unclear.
Abstract.
Author URL.
Mank JE, Wedell N, Hosken DJ (2013). Polyandry and sex-specific gene expression.
Philosophical transactions of the Royal Society of London. Series B, Biological sciences,
368(1613).
Abstract:
Polyandry and sex-specific gene expression.
Polyandry is widespread in nature, and has important evolutionary consequences for the evolution of sexual dimorphism and sexual conflict. Although many of the phenotypic consequences of polyandry have been elucidated, our understanding of the impacts of polyandry and mating systems on the genome is in its infancy. Polyandry can intensify selection on sexual characters and generate more intense sexual conflict. This has consequences for sequence evolution, but also for sex-biased gene expression, which acts as a link between mating systems, sex-specific selection and the evolution of sexual dimorphism. We discuss this and the remarkable confluence of sexual-conflict theory and patterns of gene expression, while also making predictions about transcription patterns, mating systems and sexual conflict. Gene expression is a key link in the genotype-phenotype chain, and although in its early stages, understanding the sexual selection-transcription relationship will provide significant insights into this critical association.
Abstract.
House CM, Lewis Z, Hodgson DJ, Wedell N, Sharma MD, Hunt J, Hosken DJ (2013). Sexual and natural selection both influence male genital evolution.
PLoS One,
8(5).
Abstract:
Sexual and natural selection both influence male genital evolution.
Rapid and divergent evolution of male genital morphology is a conspicuous and general pattern across internally fertilizing animals. Rapid genital evolution is thought to be the result of sexual selection, and the role of natural selection in genital evolution remains controversial. However, natural and sexual selection are believed to act antagonistically on male genital form. We conducted an experimental evolution study to investigate the combined effects of natural and sexual selection on the genital-arch lobes of male Drosophila simulans. Replicate populations were forced to evolve under lifetime monogamy (relaxed sexual selection) or lifetime polyandry (elevated sexual selection) and two temperature regimes, 25°C (relaxed natural selection) or 27°C (elevated natural selection) in a fully factorial design. We found that natural and sexual selection plus their interaction caused genital evolution. Natural selection caused some aspects of genital form to evolve away from their sexually selected shape, whereas natural and sexual selection operated in the same direction for other shape components. Additionally, sexual and natural selection tended to favour larger genitals. Thus we find that the underlying selection driving genital evolution is complex, does not only involve sexual selection, and that natural selection and sexual selection do not always act antagonistically.
Abstract.
Author URL.
2012
Sharma MD, Hunt J, Hosken DJ (2012). Antagonistic responses to natural and sexual selection and the sex-specific evolution of cuticular hydrocarbons in Drosophila simulans.
Evolution,
66(3), 665-677.
Abstract:
Antagonistic responses to natural and sexual selection and the sex-specific evolution of cuticular hydrocarbons in Drosophila simulans.
Natural and sexual selection are classically thought to oppose one another, and although there is evidence for this, direct experimental demonstrations of this antagonism are largely lacking. Here, we assessed the effects of sexual and natural selection on the evolution of cuticular hydrocarbons (CHCs), a character subject to both modes of selection, in Drosophila simulans. Natural selection and sexual selection were manipulated in a fully factorial design, and after 27 generations of experimental evolution, the responses of male and female CHCs were assessed. The effects of natural and sexual selection differed greatly across the sexes. The responses of female CHCs were generally small, but CHCs evolved predominantly in the direction of natural selection. For males, profiles evolved via sexual and natural selection, as well as through the interaction between the two, with some male CHC components only evolving in the direction of natural selection when sexual selection was relaxed. These results indicate sex-specific responses to selection, and that sexual and natural selection act antagonistically for at least some combinations of CHCs.
Abstract.
Author URL.
Price TA, Hosken DJ (2012). Evolution: why good dads win.
Curr Biol,
22(4), R135-R137.
Abstract:
Evolution: why good dads win.
Males usually do not provide parental care and with good reason, they may be caring for the offspring of someone else. But there are cases of male-only care even when certainty of paternity is low: why? a new model suggests female choice may provide the answer.
Abstract.
Author URL.
Katsuki M, Harano T, Miyatake T, Okada K, Hosken DJ (2012). Intralocus sexual conflict and offspring sex ratio.
Ecology Letters,
15(3), 193-197.
Abstract:
Intralocus sexual conflict and offspring sex ratio
Males and females frequently have different fitness optima for shared traits, and as a result, genotypes that are high fitness as males are low fitness as females, and vice versa. When this occurs, biasing of offspring sex-ratio to reduce the production of the lower-fitness sex would be advantageous, so that for example, broods produced by high-fitness females should contain fewer sons. We tested for offspring sex-ratio biasing consistent with these predictions in broad-horned flour beetles. We found that in both wild-type beetles and populations subject to artificial selection for high- and low-fitness males, offspring sex ratios were biased in the predicted direction: low-fitness females produced an excess of sons, whereas high-fitness females produced an excess of daughters. Thus, these beetles are able to adaptively bias sex ratio and recoup indirect fitness benefits of mate choice. © 2012 Blackwell Publishing Ltd/CNRS.
Abstract.
Katsuki M, Harano T, Miyatake T, Okada K, Hosken DJ (2012). Intralocus sexual conflict and offspring sex ratio.
Ecol Lett,
15(3), 193-197.
Abstract:
Intralocus sexual conflict and offspring sex ratio.
Males and females frequently have different fitness optima for shared traits, and as a result, genotypes that are high fitness as males are low fitness as females, and vice versa. When this occurs, biasing of offspring sex-ratio to reduce the production of the lower-fitness sex would be advantageous, so that for example, broods produced by high-fitness females should contain fewer sons. We tested for offspring sex-ratio biasing consistent with these predictions in broad-horned flour beetles. We found that in both wild-type beetles and populations subject to artificial selection for high- and low-fitness males, offspring sex ratios were biased in the predicted direction: low-fitness females produced an excess of sons, whereas high-fitness females produced an excess of daughters. Thus, these beetles are able to adaptively bias sex ratio and recoup indirect fitness benefits of mate choice.
Abstract.
Author URL.
Hosken DJ (2012). Rationality: Evidence must prevail.
Nature,
489(7417).
Author URL.
Sharma MD, Griffin RM, Hollis J, Tregenza T, Hosken DJ (2012). Reinvestigating good genes benefits of mate choice in Drosophila simulans.
Biological Journal of the Linnean Society,
106(2), 295-306.
Abstract:
Reinvestigating good genes benefits of mate choice in Drosophila simulans
Studies investigating the genetic benefits of female mate choice frequently find Fisherian benefits to choice, at the same time as detecting small or no good genes (viability) effects. This could be because sons trade-off viability for increased mating success and, accordingly, it has been suggested that good genes benefits should be investigated in daughters. However, good genes benefits via daughters could also be disrupted by intralocus sexual conflict. As a result, it is not clear when and if good genes benefits should accrue. We investigated potential good genes effects in Drosophila simulans using an isofemale line approach. We assessed the attractiveness of males in two different ways and then measured the longevity, as well as lifetime reproductive success, of their daughters. We also assessed potential direct benefits of female mate choice and good genes effects through the longevity of sons. We found no evidence of direct or good genes benefits to females mating with attractive males, and the failure to find good genes effects via daughters was apparently not a result of masking through intralocus sexual conflict. The results obtained in the present study are consistent with previous findings in this species, and suggest that good genes benefits are at best very small in our study population. © 2012 the Linnean Society of London.
Abstract.
Smith DT, Sirot LK, Wolfner MF, Hosken DJ, Wedell N (2012). The consequences of genetic variation in sex peptide expression levels for egg laying and retention in females.
Heredity,
109(4), 222-225.
Abstract:
The consequences of genetic variation in sex peptide expression levels for egg laying and retention in females
The accessory gland proteins (Acps) that male Drosophila melanogaster produce and transfer to females during copulation are key to male and female fitness. One Acp, the sex peptide (SP), is largely responsible for a dramatic increase in female egg laying and decrease in female receptivity after copulation. While genetic variation in male SP expression levels correlate with refractory period duration in females, it is unknown whether male SP expression influences female egg laying or if any effect of SP is mediated by SP retention in the female reproductive tract. Here we measured the amount of SP retained in the female reproductive tract after mating and female egg laying after copulating with virgin males. We found no correlation between male SP expression levels and egg laying, or the amount of SP in the female reproductive tract after mating. Additionally, the amount of SP retained in the female did not influence egg laying. These finding suggests that additional factors, such as variation in other Acps, are important for the retention of SP in females and its quantitative effects on egg laying. It also shows that egg laying and refractory period response to SP is at least partially uncoupled. © 2012 Macmillan Publishers Limited all rights reserved.
Abstract.
Sharma MD, Mitchell C, Hunt J, Tregenza T, Hosken DJ (2012). The genetics of cuticular hydrocarbon profiles in the fruit fly Drosophila simulans.
J Hered,
103(2), 230-239.
Abstract:
The genetics of cuticular hydrocarbon profiles in the fruit fly Drosophila simulans.
Female mate choice is one mechanism of sexual selection and, provided there is adequate genetic variation in the male traits that are the target of this selection, they will evolve via female choice. Cuticular hydrocarbons (CHCs) are important in Drosophila mate choice, but relatively little is known about the underlying genetic architecture of CHC profiles in Drosophila simulans. Here, we used gas chromatography-mass spectrometry to investigate patterns of genetic variation in the CHC profiles of male and female D. simulans using isofemale lines. We found substantial genetic variation for CHC profiles and individual CHC components, and individual CHCs were frequently strongly genetically correlated, with a tendency for negative covariance between long- and short-chain CHCs in males. Intersexual genetic covariances were often weak and frequently differed in sign. These findings are novel and significant, highlighting the previously unexplored genetic architecture of CHCs in D. simulans and suggest that this architecture may facilitate sex-specific CHC evolution.
Abstract.
Author URL.
Rostant WG, Wedell N, Hosken DJ (2012). Transposable elements and insecticide resistance.
Adv Genet,
78, 169-201.
Abstract:
Transposable elements and insecticide resistance.
Transposable elements (TEs) are mobile DNA sequences that are able to copy themselves within a host genome. They were initially characterized as selfish genes because of documented or presumed costs to host fitness, but it has become increasingly clear that not all TEs reduce host fitness. A good example of TEs benefiting hosts is seen with insecticide resistance, where in a number of cases, TE insertions near specific genes confer resistance to these man-made products. This is particularly true of Accord and associated TEs in Drosophila melanogaster and Doc insertions in Drosophila simulans. The first of these insertions also has sexually antagonistic fitness effects in the absence of insecticides, and although the magnitude of this effect depends on the genetic background in which Accord finds itself, this represents an excellent example of intralocus sexual conflict where the precise allele involved is well characterized. We discuss this finding and the role of TEs in insecticide resistance. We also highlight areas for further research, including the need for surveys of the prevalence and fitness consequences of the Doc insertion and how Drosophila can be used as models to investigate resistance in pest species.
Abstract.
Author URL.
2011
Brown AR, Bickley LK, Le Page G, Hosken DJ, Paull GC, Hamilton PB, Owen SF, Robinson J, Sharpe AD, Tyler CR, et al (2011). Are toxicological responses in laboratory (inbred) zebrafish representative of those in outbred (wild) populations? - a case study with an endocrine disrupting chemical.
Environ Sci Technol,
45(9), 4166-4172.
Abstract:
Are toxicological responses in laboratory (inbred) zebrafish representative of those in outbred (wild) populations? - a case study with an endocrine disrupting chemical.
Laboratory animals tend to be more inbred and less genetically diverse than wild populations, and thus may differ in their susceptibility to chemical stressors. We tested this hypothesis by comparing the responses of related inbred (theoretical inbreeding F(IT) = n + 0.25) and outbred (F(IT) = n) zebrafish (Danio rerio) WIK/Wild family lines to an endocrine disrupting chemical, clotrimazole. Exposure of inbred and outbred zebrafish to 2.9 μg clotrimazole/L had no effect on survival, growth, or gonadal development. Exposure of both lines to 43.7 μg clotrimazole/L led to male-biased sex ratios compared with controls (87% versus 55% and 92% vs 64%, for inbred and outbred males, respectively), advanced germ cell development, and reduced plasma 11-ketotestosterone concentrations in males. However, outbred males (but not inbred males) developed testis that were more than twice the weight of controls, which corresponded with a proliferation of Leydig cells and maintenance of the expression (rather than down-regulation occurring in inbreds) of gonadal aromatase (cyp19a1a) and insulin-like growth factor (igf1). Our results illustrate that the effects of an endocrine disrupting chemical (clotrimazole) on some end points (here testis development) can differ between inbred and outbred zebrafish. This highlights the need for reporting pedigree/genetic information and consistency in the responses of laboratory animals (e.g. by using model compounds as positive controls).
Abstract.
Author URL.
Smith DT, Hosken DJ, Rostant WG, Yeo M, Griffin RM, Bretman A, Price TAR, Ffrench-Constant RH, Wedell N (2011). DDT resistance, epistasis and male fitness in flies.
J Evol Biol,
24(6), 1351-1362.
Abstract:
DDT resistance, epistasis and male fitness in flies.
In Drosophila melanogaster, the DDT resistance allele (DDT-R) is beneficial in the presence of DDT. Interestingly, DDT-R also elevates female fitness in the absence of DDT and existed in populations before DDT use. However, DDT-R did not spread regardless of DDT-independent selective advantages in females. We ask whether sexual antagonism could explain why DDT-R did not spread before pesticide use. We tested pre- and post-copulatory male fitness correlates in two genetic backgrounds into which we backcrossed the DDT-R allele. We found costs to DDT-R that depended on the genetic background in which DDT-R was found and documented strong epistasis between genetic background and DDT-R that influenced male size. Although it remains unclear whether DDT-R is generally sexually antagonistic, or whether the fitness costs noted would be sufficient to retard the spread of DDT-R in the absence of DDT, general fitness advantages to DDT-R in the absence of DDT may be unlikely.
Abstract.
Author URL.
Bambini L, Kofoky AF, Mbohoahy T, Ralisata M, Manjoazy T, Hosken DJ, Jenkins RKB (2011). Do bats need trees? habitat use of two malagasy hipposiderid bats triaenops furculus and T. menamena in the dry Southwest.
Hystrix,
22(1), 81-92.
Abstract:
Do bats need trees? habitat use of two malagasy hipposiderid bats triaenops furculus and T. menamena in the dry Southwest
Habitat degradation and loss threaten the survival of many bat species. Recent studies in Madagascar however have found some species are present in areas of low forest cover even though their echolocation calls and wing morphology suggest they are able to forage in forests. The present study investigated habitat use and prey selection in two sympatric hipposiderid bats, Triaenops furculus and T. menamena, in the dry southwest of Madagascar. The study colony occupied a cave in limestone karst surrounded by intact spiny bush and several secondary or degraded habitats. We used bat detectors and radiotracking to determine habitat use, and faecal analysis and invertebrate sampling to assess prey selection. Spiny bush, the dominant habitat type in the study area, was used less than predicted from its availability, based on satellite imagery and ground-based habitat mapping. Areas containing large trees were used by radiotracked bats in approximate proportion to their availability and acoustic sampling revealed highest bat activity in this habitat. The radio-tracked individuals used agricultural land more than expected from its availability. A significant difference was found in the proportion of Lepidoptera in the faeces of the two species, with T furculus showing a preference for moths. Triaenops furculus also selected Coleoptera, whereas T. menamena preferred mainly Hemiptera. While this study did not identify a strong association with forested habitats in T. furculus or T. menamena, it remains to be established whether the bats forage in a sub-optimal habitat due to their preference for roosting in the nearby karst caves.
Abstract.
Hosken DJ (2011). Gene duplication might not resolve intralocus sexual conflict.
Trends Ecol Evol,
26(11), 556-557.
Author URL.
Okada K, Pitchers WR, Sharma MD, Hunt J, Hosken DJ (2011). Longevity, calling effort, and metabolic rate in two populations of cricket.
Behavioral Ecology and Sociobiology,
65(9), 1773-1778.
Abstract:
Longevity, calling effort, and metabolic rate in two populations of cricket
Intraspecific variation in a resting metabolic rate (RMR) is likely to be an important determinant of energetic-resource use and may influence the resources subsequently available for allocation to traits not directly associated with somatic maintenance. The influence of RMR on resource availability could be especially important for condition-dependent sexual traits, such as cricket calls, that are themselves energetically costly to produce. RMR may also be associated with longevity, either negatively because individuals with a high RMR burn resources faster and die young, or positively as individuals with high RMR are more able to accrue resources to fuel survival. Additionally, the associations between RMR and other characters may vary across populations if differential selection or drift shapes these traits. Here we tested for differences in RMR, body mass, calling effort, and longevity in two populations of cricket Gryllodes sigillatus and then evaluated the potential influence of RMR on calling and longevity. We find that RMR, calling effort, and longevity varied across populations, but mass did not. Controlling for population and mass, RMR was not significantly associated with calling effort, but was negatively associated with longevity. These findings suggest that male crickets that live fast die young. © 2011 Springer-Verlag.
Abstract.
Okada K, Blount JD, Sharma MD, Snook RR, Hosken DJ (2011). Male attractiveness, fertility and susceptibility to oxidative stress are influenced by inbreeding in Drosophila simulans.
J Evol Biol,
24(2), 363-371.
Abstract:
Male attractiveness, fertility and susceptibility to oxidative stress are influenced by inbreeding in Drosophila simulans.
Inbreeding frequently leads to inbreeding depression, a reduction in the trait values of inbred individuals. Inbreeding depression has been documented in sexually selected characters in several taxa, and while there is correlational evidence that male fertility is especially susceptible to inbreeding depression, there have been few direct experimental examinations of this. Here, we assessed inbreeding depression in male fertility and a range of other male fitness correlates in Drosophila simulans. We found that male fertility and attractiveness were especially susceptible to inbreeding depression. Additionally, levels of testicular oxidative stress were significantly elevated in inbred males, although sperm viability did not differ between inbred and outbred males. Copulation duration, induction of oviposition, and the proportion of eggs hatching did not differ for females mated to inbred or outbred males. Nevertheless, our results clearly show that key male fitness components are impaired by inbreeding and provide evidence that aspects of male fertility are especially susceptible to inbreeding depression.
Abstract.
Author URL.
Sinclair BJ, Bretman A, Tregenza T, Tomkins JL, Hosken DJ (2011). Metabolic rate does not decrease with starvation in Gryllus bimaculatus when changing fuel use is taken into account.
Physiological Entomology,
36(1), 84-89.
Abstract:
Metabolic rate does not decrease with starvation in Gryllus bimaculatus when changing fuel use is taken into account
Many behavioural traits are considered to be condition-dependent, reflecting the differential allocation of resources to fitness-related traits and maintenance, although the physiological underpinnings of condition dependence are not well understood. In the present study, the hypothesis that condition dependence in male Gryllus bimaculatus De Geer is mediated by a decrease in metabolic rate with declining condition is tested. CO2 production is measured by flow-through respirometry, with insect condition manipulated through starvation. Crickets starved for 7 days have lower CO2 emission rates than individuals starved for only 24 h. However, carbohydrate reserves are depleted in the first 3 days, suggesting that the initial metabolism is primarily fuelled by carbohydrate, with a shift to lipid stores after 3 days. If the metabolic rate is estimated using respiratory quotients reflecting this shift in fuels, there is no difference in metabolic rate between crickets starved for 24 h and 7 days, suggesting that metabolic rate does not decrease with declining condition. This implies that a decrease in metabolic rate during starvation may not be a general pattern in insects, and emphasizes the need to consider fuel use during metabolic rate estimation in starvation studies. © 2010 the Authors. Physiological Entomology © 2010 the Royal Entomological Society.
Abstract.
Sharma MD, Tregenza T, Hosken DJ (2011). Sex combs, allometry, and asymmetry in Drosophila.
Biological Journal of the Linnean Society,
103(4), 923-934.
Abstract:
Sex combs, allometry, and asymmetry in Drosophila
There has been recent debate about the expected allometry of sexually-selected traits. Although sexually-selected traits exhibit a diversity of allometric patterns, signalling characters are frequently positively allometric. By contrast, insect genitalia tend to be negatively allometric, although the allometry of nongenital sexually-selected characters in insects is largely unknown (with some notable exceptions). It has also been suggested that there should be a negative association between the asymmetry and size of bilaterally-paired, sexually-selected traits, although this claim is controversial. We assessed the allometry and asymmetry (fluctuating asymmetry, FA) of a nongenital contact-courtship structure, the sex comb, in replicate populations of three species of Drosophila (we also measured wing FA). Sex combs are sexually-selected characters used to grasp the female's abdomen and genitalia and to spread her wings prior to and during copulation. Although species differed in the size of the sex combs, all combs were positively allometric, and comb allometry did not generally differ significantly between species or populations. Comb and wing asymmetry did vary across species, although not across populations of the same species. However, FA was trait specific and was never negatively associated with trait size. © 2011 the Linnean Society of London.
Abstract.
Hosken DJ, House CM (2011). Sexual selection.
Curr Biol,
21(2), R62-R65.
Abstract:
Sexual selection.
Sexual selection is a concept that has probably been misunderstood and misrepresented more than any other idea in evolutionary biology, confusion that continues to the present day. We are not entirely sure why this is, but sexual politics seems to have played its role, as does a failure to understand what sexual selection is and why it was initially invoked. While in some ways less intuitive than natural selection, sexual selection is conceptually identical to it, and evolution via either mechanism will occur given sufficient genetic variation. Recent claims that sexual selection theory is fundamentally flawed are simply wrong and ignore an enormous body of evidence that provides a bedrock of support for this major mechanism of organic evolution. In fact it is partly due to this solid foundation that current research has largely shifted from documenting whether or not sexual selection occurs, to addressing more complex evolutionary questions.
Abstract.
Author URL.
Mank JE, Hosken DJ, Wedell N (2011). Some inconvenient truths about sex chromosome dosage compensation and the potential role of sexual conflict.
Evolution,
65(8), 2133-2144.
Abstract:
Some inconvenient truths about sex chromosome dosage compensation and the potential role of sexual conflict.
Sex chromosome dosage compensation was once thought to be required to balance gene expression levels between sex-linked and autosomal genes in the heterogametic sex. Recent evidence from a range of animals has indicated that although sex chromosome dosage compensation exists in some clades, it is far from a necessary companion to sex chromosome evolution, and is in fact rather rare in animals. This raises questions about why complex dosage compensation mechanisms arise in some clades when they are not strictly needed, and suggests that the role of sex-specific selection in sex chromosome gene regulation should be reassessed. We show there exists a tremendous diversity in the mechanisms that regulate gene dosage and argue that sexual conflict may be an overlooked agent responsible for some of the variation seen in sex chromosome gene dose regulation.
Abstract.
Author URL.
Snook RR, Hosken DJ, Karr TL (2011). The biology and evolution of polyspermy: insights from cellular and functional studies of sperm and centrosomal behavior in the fertilized egg.
Reproduction,
142(6), 779-792.
Abstract:
The biology and evolution of polyspermy: insights from cellular and functional studies of sperm and centrosomal behavior in the fertilized egg.
Recent studies of centrosome biogenesis, microtubule dynamics, and their management point to their role in mediating conditions such as aging and cancer. Centrosome dysfunction is also a hallmark of pathological polyspermy. Polyspermy occurs when the oocyte is penetrated by more than one sperm and can be pathological because an excess of centrosomes compromises development. However, in some taxa, multiple sperm enter the egg with no apparent adverse effect on zygote viability. Thus, some taxa can manage excess centrosomes and represent cases of non-pathological polyspermy. While these two forms of polyspermy have long been known, we argue that there is limited understanding of the proximate and ultimate processes that underlie this taxonomic variation in the outcome of polyspermy and that studying this variation could help uncover the control and role(s) of centrosomes during fertilization in particular, but also mitosis in general. To encourage such studies we: 1) describe taxonomic differences in the outcome of polyspermy, 2) discuss mechanistic aspects of reproductive biology that may contribute to the different consequences of polyspermy, and 3) outline the potential selective events that could lead to the evolution of variation in polyspermy outcomes. We suggest that novel insights into centrosome biology may occur by cooperative studies between reproductive and evolutionary biologists focusing on the mechanisms generating variation in the fitness consequences of polyspermy, and in the taxonomic distribution of all these events. The consequent discoveries of these studies may lead to informative insights into cancer and aging along with other centrosome-related diseases and syndromes.
Abstract.
Author URL.
Gay L, Hosken DJ, Eady P, Vasudev R, Tregenza T (2011). The evolution of harm--effect of sexual conflicts and population size.
Evolution,
65(3), 725-737.
Abstract:
The evolution of harm--effect of sexual conflicts and population size.
Conflicts of interest between mates can promote the evolution of male traits that reduce female fitness and that drive coevolution between the sexes. The rate of adaptation depends on the intensity of selection and its efficiency, which depends on drift and genetic variability. This leads to the largely untested prediction that coevolutionary adaptations such as those driven by sexual conflict should evolve faster in large populations. We tested this using the bruchid beetle Callosobruchus maculatus, a species where harm inflicted by males is well documented. Although most experimental evolution studies remove sexual conflict, we reintroduced it in populations in which it had been experimentally removed. Both population size and standing genetic variability were manipulated in a factorial experimental design. After 90 generations of relaxed conflict (monogamy), the reintroduction of sexual conflicts for 30 generations favored males that harmed females and females that were more resistant to the genital damage inflicted by males. Males evolved to become more harmful when population size was large rather than when initial genetic variation was enriched. Our study shows that sexual selection can create conditions in which males can benefit from harming females and that selection may tend to be more intense and effective in larger populations.
Abstract.
Author URL.
Gay L, Brown E, Tregenza T, Pincheira-Donoso D, Eady PE, Vasudev R, Hunt J, Hosken DJ (2011). The genetic architecture of sexual conflict: male harm and female resistance in Callosobruchus maculatus.
J Evol Biol,
24(2), 449-456.
Abstract:
The genetic architecture of sexual conflict: male harm and female resistance in Callosobruchus maculatus.
Males harm females during mating in a range of species. This harm is thought to evolve because it is directly or indirectly beneficial to the male, despite being costly to his mate. The resulting sexually antagonistic selection can cause sexual arms races. For sexually antagonistic co-evolution to occur, there must be genetic variation for traits involved in female harming and susceptibility to harm, but even then intersexual genetic correlations could facilitate or impede sexual co-evolution. Male Callosobruchus maculatus harm their mates during copulation by damaging the female's reproductive tract. However, there have been no investigations of the genetic variation in damage or in female susceptibility to damage, nor has the genetic covariance between these characters been assessed. Here, we use a full-sib/half-sib breeding design to show that male damage is heritable, whereas female susceptibility to damage is much less so. There is also a substantial positive genetic correlation between the two, suggesting that selection favouring damaging males will increase the prevalence of susceptible females. We also provide evidence consistent with intralocus sexual conflict in this species.
Abstract.
Author URL.
2010
Taylor ML, Wedell N, Hosken DJ (2010). Attractive males do not sire superior daughters.
Evolutionary Ecology,
24(1), 195-205.
Abstract:
Attractive males do not sire superior daughters
Much of the recent work on the evolution of female choice has focused on the relative influence of direct and indirect benefits, and particularly whether direct costs can be offset by indirect benefits. Studies investigating whether attractive males benefit females by increasing the viability of their offspring often report mating advantages to sons consistent with the Fisher process, while detecting no or weak viability benefits. One potential reason for this is that sons may trade-off viability benefits with investment in costly traits that enhance mating success, leading to the suggestion that viability benefits may be better detected by examining daughters' fitness. Here we investigate the relationship between male attractiveness and daughters' fitness in Drosophila simulans. We measured daughter (and dam) lifetime reproductive success and longevity. We found no evidence that attractive males sire high fitness daughters. Additionally, neither daughters nor dams gained direct benefits from mating with attractive males. However, aspects of daughters' fitness were related to dam characters. © Springer Science+Business Media B.V. 2009.
Abstract.
Sharma MD, Tregenza T, Hosken DJ (2010). Female mate preferences in Drosophila simulans: evolution and costs.
J Evol Biol,
23(8), 1672-1679.
Abstract:
Female mate preferences in Drosophila simulans: evolution and costs.
Female mate preference is central to sexual selection, and all indirect benefit models require that there is genetic variation in female preference. This has rarely been tested however, with relatively few studies documenting heritable variation in female preference and even fewer that have directly selected on mate preference to unequivocally show that it can evolve. Additionally, costs of mate preference are poorly understood even though these have implications for preference evolution. We selected on female preference for ebony-males in replicate Drosophila simulans lines, and generated a rapid evolutionary response in both replicates, with the proportion of females mating with ebony-males increasing from approximately 5% to 30% after five generations of selection. This increase was independent of changes in ebony-males as only females were included in our selection regime. We could detect no cost to mate preference itself other than that associated with the fitness consequences of mating with ebony males.
Abstract.
Author URL.
Arnqvist G, Dowling DK, Eady P, Gay L, Tregenza T, Tuda M, Hosken DJ (2010). Genetic architecture of metabolic rate: environment specific epistasis between mitochondrial and nuclear genes in an insect.
Evolution,
64(12), 3354-3363.
Abstract:
Genetic architecture of metabolic rate: environment specific epistasis between mitochondrial and nuclear genes in an insect.
The extent to which mitochondrial DNA (mtDNA) variation is involved in adaptive evolutionary change is currently being reevaluated. In particular, emerging evidence suggests that mtDNA genes coevolve with the nuclear genes with which they interact to form the energy producing enzyme complexes in the mitochondria. This suggests that intergenomic epistasis between mitochondrial and nuclear genes may affect whole-organism metabolic phenotypes. Here, we use crossed combinations of mitochondrial and nuclear lineages of the seed beetle Callosobruchus maculatus and assay metabolic rate under two different temperature regimes. Metabolic rate was affected by an interaction between the mitochondrial and nuclear lineages and the temperature regime. Sequence data suggests that mitochondrial genetic variation has a role in determining the outcome of this interaction. Our genetic dissection of metabolic rate reveals a high level of complexity, encompassing genetic interactions over two genomes, and genotype × genotype × environment interactions. The evolutionary implications of these results are twofold. First, because metabolic rate is at the root of life histories, our results provide insights into the complexity of life-history evolution in general, and thermal adaptation in particular. Second, our results suggest a mechanism that could contribute to the maintenance of nonneutral mtDNA polymorphism.
Abstract.
Author URL.
Narraway C, Hunt J, Wedell N, Hosken DJ (2010). Genotype by envirnment interactions for female preference. Journal of Evolutionary Biology, 23, 2550-2557.
Harano T, Okada K, Nakayama S, Miyatake T, Hosken DJ (2010). Intralocus sexual conflict unresolved by sex-limited trait expression.
Curr Biol,
20(22), 2036-2039.
Abstract:
Intralocus sexual conflict unresolved by sex-limited trait expression.
Sexually antagonistic selection generates intralocus sexual conflict, an evolutionary tug-of-war between males and females over optimal trait values [1-4]. Although the potential for this conflict is universal, the evolutionary importance of intralocus conflict is controversial because conflicts are typically thought to be resolvable through the evolution of sex-specific trait development [1-8]. However, whether sex-specific trait expression always resolves intralocus conflict has not been established. We assessed this with beetle populations subjected to bidirectional selection on an exaggerated sexually selected trait, the mandible. Mandibles are only ever developed in males for use in male-male combat, and larger mandibles increase male fitness (fighting [9, 10] and mating success, as we show here). We find that females from populations selected for larger male mandibles have lower fitness, whereas females in small-mandible populations have highest fitness, even though females never develop exaggerated mandibles. This is because mandible development changes genetically correlated characters, resulting in a negative intersexual fitness correlation across these populations, which is the unmistakable signature of intralocus sexual conflict [1]. Our results show that sex-limited trait development need not resolve intralocus sexual conflict, because traits are rarely, if ever, genetically independent of other characters [11]. Hence, intralocus conflict resolution is not as easy as currently thought.
Abstract.
Author URL.
Brown EA, Gay L, Vasudev R, Tregenza T, Eady PE, Hosken DJ (2010). Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles (vol 103, pg 340, 2009).
HEREDITY,
105(6), 576-576.
Author URL.
Dobler R, Hosken DJ (2010). Response to selection and realized heritability of sperm length in the yellow dung fly (Scathophaga stercoraria).
Heredity (Edinb),
104(1), 61-66.
Abstract:
Response to selection and realized heritability of sperm length in the yellow dung fly (Scathophaga stercoraria).
Sperm length shows considerable phenotypic variation both inter- and intra-specifically, but a general explanation for this variation is lacking. In addition, our understanding of the genetic variation underlying sperm length variation is also limited because there have been few studies on the genetics of sperm size. One factor that could explain the variation in sperm length is that length influences sperm competitiveness, and there is some evidence for this. However, in yellow dung flies (Scathophaga stercoraria), microevolutionary responses to experimental variation at levels of sperm competition indicate that sperm length does not influence sperm competitiveness, although this lack of response may simply indicate sperm length lacks evolutionary potential (that is, it is constrained in some way), in spite of evidence that sperm length is heritable. Here we report on a laboratory study, in which we artificially selected upwards and downwards on sperm length in S. stercoraria. We found that sperm length significantly diverged after four generations of selection, but the response to selection was asymmetrical: upward selection generated a rapid response, but downward did not. We estimated the realized heritability of sperm length to be approximately 50%, which is consistent with previous sire-son estimates. We also assessed the fertility of males from upward and downward lines and found they did not differ. Results are discussed in the context of sperm competition.
Abstract.
Author URL.
Punzalan D, Hosken DJ (2010). Sexual dimorphism: why the sexes are (and are not) different.
Curr Biol,
20(22), R972-R973.
Abstract:
Sexual dimorphism: why the sexes are (and are not) different.
Sex differences often call sexual selection to mind; however, a new damselfly study cautions on being too hasty, and implicates viability selection in the evolution of male and female colouration.
Abstract.
Author URL.
Okada K, Hosken DJ (2010). Sperm competition: discrimination isn't always bad.
Curr Biol,
20(10), R444-R446.
Abstract:
Sperm competition: discrimination isn't always bad.
Observing sperm in competition has been limited by our ability to discriminate between males' sperm. Recent work has overcome this obstacle, while another study reports on seminal fluid with very specific spermicidal activity, suggesting discrimination is easy for some.
Abstract.
Author URL.
Ingleby FC, Hunt J, Hosken DJ (2010). The role of genotype-by-environment interactions in sexual selection.
J Evol Biol,
23(10), 2031-2045.
Abstract:
The role of genotype-by-environment interactions in sexual selection.
Genotype-by-environment interactions (GxEs) in naturally selected traits have been extensively studied, but the impact of GxEs on sexual selection has only recently begun to receive attention. Here, we review recent models and consider how GxEs might affect the evolution of sexual traits through influencing sexual signal reliability and also how GxEs may influence variation in sexually selected traits and the process of reproductive isolation. We then assess the current empirical literature on GxEs in sexual selection and conclude by highlighting areas that need additional work. Research on GxEs and sexual selection is an important new area of study for the discipline, which has largely focused on relatively simple mate choice/competition scenarios to date. Investigators now need to apply this knowledge to more complex, but realistic, situations, to more fully explore the evolution of sexual traits, and in this review we suggest potentially useful directions for future research.
Abstract.
Author URL.
2009
Lessells CM, Snook RR, Hosken DJ (2009). 2 the evolutionary origin and maintenance of sperm selection for a small, motile gamete mating type. In (Ed) Sperm Biology, 43-67.
Pitnick S, Hosken DJ, Birkhead TR (2009). 3 Sperm morphological diversity. In (Ed) Sperm Biology, 69-149.
Hosken DJ, Kunz TH (2009). But is it male lactation or not?. Trends Ecol Evol, 24(7), 355-355.
Gay L, Eady PE, Vasudev R, Hosken DJ, Tregenza T (2009). Costly sexual harassment in a beetle.
Physiological Entomology,
34(1), 86-92.
Abstract:
Costly sexual harassment in a beetle
The optimal number of mating partners for females rarely coincides with that for males, leading to sexual conflict over mating frequency. In the bruchid beetle Callosobruchus maculatus, the fitness consequences to females of engaging in multiple copulations are complex, with studies demonstrating both costs and benefits to multiple mating. However, females kept continuously with males have a lower lifetime egg production compared with females mated only once and then isolated from males. This reduction in fitness may be a result of damage caused by male genitalia, which bear spines that puncture the female's reproductive tract, and/or toxic elements in the ejaculate. However, male harassment rather than costs of matings themselves could also explain the results. In the present study, the fitness costs of male harassment for female C. maculatus are estimated. The natural refractory period of females immediately after their first mating is used to separate the cost of harassment from the cost of mating. Male harassment results in females laying fewer eggs and this results in a tendency to produce fewer offspring. The results are discussed in the context of mate choice and sexual selection. © 2008 the Royal Entomological Society.
Abstract.
Gay L, Eady PE, Vasudev R, Hosken DJ, Tregenza T (2009). Does reproductive isolation evolve faster in larger populations via sexually antagonistic coevolution?.
Biol Lett,
5(5), 693-696.
Abstract:
Does reproductive isolation evolve faster in larger populations via sexually antagonistic coevolution?
Sexual conflict over reproductive investment can lead to sexually antagonistic coevolution and reproductive isolation. It has been suggested that, unlike most models of allopatric speciation, the evolution of reproductive isolation through sexually antagonistic coevolution will occur faster in large populations as these harbour greater levels of standing genetic variation, receive larger numbers of mutations and experience more intense sexual selection. We tested this in bruchid beetle populations (Callosobruchus maculatus) by manipulating population size and standing genetic variability in replicated lines derived from founders that had been released from sexual conflict for 90 generations. We found that after 19 generations of reintroduced sexual conflict, none of our treatments had evolved significant overall reproductive isolation among replicate lines. However, as predicted, measures of reproductive isolation tended to be greater among larger populations. We discuss our methodology, arguing that reproductive isolation is best examined by performing a matrix of allopatric and sympatric crosses whereas measurement of divergence requires crosses with a tester line.
Abstract.
Author URL.
Brown AR, Hosken DJ, Balloux F, Bickley LK, LePage G, Owen SF, Hetheridge MJ, Tyler CR (2009). Genetic variation, inbreeding and chemical exposure--combined effects in wildlife and critical considerations for ecotoxicology.
Philos Trans R Soc Lond B Biol Sci,
364(1534), 3377-3390.
Abstract:
Genetic variation, inbreeding and chemical exposure--combined effects in wildlife and critical considerations for ecotoxicology.
Exposure to environmental chemicals can have negative consequences for wildlife and even cause localized population extinctions. Resistance to chemical stress, however, can evolve and the mechanisms include desensitized target sites, reduced chemical uptake and increased metabolic detoxification and sequestration. Chemical resistance in wildlife populations can also arise independently of exposure and may be spread by gene flow between populations. Inbreeding-matings between closely related individuals-can have negative fitness consequences for natural populations, and there is evidence of inbreeding depression in many wildlife populations. In some cases, reduced fitness in inbred populations has been shown to be exacerbated under chemical stress. In chemical testing, both inbred and outbred laboratory animals are used and for human safety assessments, iso-genic strains (virtual clones) of mice and rats are often employed that reduce response variation, the number of animals used and associated costs. In contrast, for environmental risk assessment, strains of animals are often used that have been selectively bred to maintain heterozygosity, with the assumption that they are better able to predict adverse effects in wild, genetically variable, animals. This may not necessarily be the case however, as one outbred strain may not be representative of another or of a wild population. In this paper, we critically discuss relationships between genetic variation, inbreeding and chemical effects with the intention of seeking to support more effective chemical testing for the protection of wildlife.
Abstract.
Author URL.
Hosken DJ, Price TAR (2009). Genital evolution: the traumas of sex.
Curr Biol,
19(13), R519-R521.
Abstract:
Genital evolution: the traumas of sex.
Copulating males usually insert their penis into the female and ejaculate in her reproductive tract; but in some species, males are more invasive, puncturing the female body-wall and inseminating directly into her body-cavity. A spider has just been added to this list and new perspectives provided on why males harm females during copulation in the first place.
Abstract.
Author URL.
Martin OY, Hosken DJ (2009). Longevity and developmental stability in the dung fly Sepsis cynipsea, as affected by the ectoparasitic mite, Pediculoides mesembrinae.
J Insect Sci,
9, 1-9.
Abstract:
Longevity and developmental stability in the dung fly Sepsis cynipsea, as affected by the ectoparasitic mite, Pediculoides mesembrinae.
Fluctuating asymmetry (FA) is a widely employed measure of developmental stability. It has been found to increase with many stressors including parasite infection. Associations between parasites and FA may exist for several reasons in addition to parasites being the direct cause of increased FA. Developmentally stable individuals may have superior immune systems, and be less susceptible to parasite infection, and/or may be less exposed to parasites than developmentally unstable ones. Mites negatively impact host fitness in a number of insects, and if FA is a reflection of general genetic quality, as has been proposed, associations between mite number and FA are predicted. Potential relationships were investigated between an ectoparasitic mite, Pediculoides mesembrinae (Canestrini) (Phthiraptera: Menoponidae) and FA in the common dung fly Sepsis cynipsea (L.) (Diptera: Sepsidae). While it was found that mite infested flies died much faster than flies without mites, indicating that mites indeed stress their hosts, counter to expectations, no associations between mites and FA were found in any analyses. Additionally, FA in mite-infected flies generally did not differ from previously published FA data from uninfected S. cynipsea. Nevertheless, parasitized males tended to be somewhat less asymmetrical than non-parasitized males, but based on our data, it does not appear that mite infestation is generally associated with developmental stability in S. cynipsea.
Abstract.
Author URL.
Kunz TH, Hosken DJ (2009). Male lactation: why, why not and is it care?.
Trends Ecol Evol,
24(2), 80-85.
Abstract:
Male lactation: why, why not and is it care?
Mammals are characterised by their ability to provision offspring with milk, but lactation is normally restricted to females. Why do most males not share this trait? the morphological and physiological modifications necessary for male lactation are possible and, although restrictive, the ecological factors that could select for male lactation seem common enough. Until quite recently, there was no evidence for male lactation in wild mammals, but it has now been reported in two species of Old World fruit bats. Here we review mechanisms that can cause milk production in males and also consider the possibility that male lactation in these bats is a unique adaptive phenomenon.
Abstract.
Author URL.
Hosken DJ, Stockley P, Tregenza T, Wedell N (2009). Monogamy and the battle of the sexes.
Annu Rev Entomol,
54, 361-378.
Abstract:
Monogamy and the battle of the sexes.
Sexual conflict has been suggested to be important in the evolution of reproductive traits, with much recent theoretical and empirical evidence emphasizing its role in generating sexually antagonistic coevolution in the context of promiscuous mating. Here we shift attention to the role of sexual conflict in a monogamous mating context. Conflicts can arise, for example, when males are successful in imposing monandry at a cost to female fitness, or when females impose monogyny on males. Conflict over remating can also generate monogamy. For example, when males invest heavily in attempting to impose female monandry, the cost of their investment may prevent them from securing additional mates. We emphasize that sexual conflicts need not always generate sexually antagonistic coevolution, and that it is important to consider whether mating decisions are controlled primarily by males or females. Finally, we briefly discuss approaches to distinguish between conflict and classical modes of sexual selection, as this highlights difficulties associated with deciding whether monogamy is enforced by one sex or the other. We suggest that documenting the current fitness consequences of mate choice and mating patterns provides insight into the relative importance of classic and conflict modes of selection.
Abstract.
Author URL.
Hosken DJ (2009). More acclaim for Darwin's theory of sexual selection.
Nature,
458(7240).
Author URL.
Brown EA, Gay L, Vasudev R, Tregenza T, Eady PE, Hosken DJ (2009). Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles.
Heredity (Edinb),
103(4), 340-345.
Abstract:
Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles.
Reproduction can be costly and is predicted to trade-off against other characters. However, while these trade-offs are well documented for females, there has been less focus on aspects of male reproduction. Furthermore, those studies that have looked at males typically only investigate phenotypic associations, with the underlying genetics often ignored. Here, we report on phenotypic and genetic trade-offs in male reproductive effort in the seed beetle, Callosobruchus maculatus. We find that the duration of a male's first copulation is negatively associated with subsequent male survival, phenotypically and genetically. Our results are consistent with life-history theory and suggest that like females, males trade-off reproductive effort against longevity.
Abstract.
Author URL.
Higgins SL, Hosken DJ, Wedell N (2009). Phenotypic and genetic variation in male genitalia in the seedbug, Lygaeus equestris (Heteroptera).
Biological Journal of the Linnean Society,
98(2), 400-405.
Abstract:
Phenotypic and genetic variation in male genitalia in the seedbug, Lygaeus equestris (Heteroptera)
Male genitalia evolve through sexual selection and, in insects, tend to show negative static allometry, low phenotypic variation, and are usually relatively small. Much less is known about the genetic variation and heritability of male genitalia. Additionally, in instances where the intromittent organ is greatly elongated, it is unclear whether typical patterns of genital scaling and variation also apply. In the present study, we investigated the allometry, variation, and heritability of male genital length in the seedbug, Lygaeus equestris, a species with a greatly elongated intromittent organ (i.e. almost as long as male body size). We found that genital length was negatively allometric, in spite of its great length, and was no more variable than nongenital traits. Additionally, genital length was significantly heritable and had considerable evolvability. © 2009 the Linnean Society of London.
Abstract.
Hosken DJ, Martin OY, Wigby S, Chapman T, Hodgson DJ (2009). Sexual conflict and reproductive isolation in flies.
Biol Lett,
5(5), 697-699.
Abstract:
Sexual conflict and reproductive isolation in flies.
Sexual conflict is predicted to generate more rapid reproductive isolation between larger populations. While there is some empirical support for this, the data are inconsistent and, additionally, there has been criticism of some of the evidence. Here we reanalyse two experimental-evolution datasets using an isolation index widely applied in the speciation literature. We find evidence for reproductive isolation through sexual conflict in Sepsis cynipsea, but not in Drosophila melanogaster, and this occurred to a greater degree in larger populations, which is consistent with previous findings.
Abstract.
Author URL.
Taylor ML, Sharma MD, Hosken DJ (2009). Sexual selection in flies: a comparison of Drosophila simulans and D. melanogaster.
Animal Biology,
59(4), 391-402.
Abstract:
Sexual selection in flies: a comparison of Drosophila simulans and D. melanogaster
The traditional view of sexual selection via female mate choice is that female preference for certain males either has no net fitness cost or is beneficial to overall female fitness. A more contemporary view is that preferred males can at times reduce female fitness. This view has arisen from the realisation that conflict between the sexes is an inevitable feature of sexual reproduction, as each sex necessarily has a different agenda for maximizing fitness. Despite the hailing of sexual conflict as a paradigm shift and its prevalence in the recent sexual selection literature, compelling evidence that attractive males reduce female fitness remains taxonomically restricted. Here we review the findings of a series of investigations into the fitness consequences of female preference in the fly Drosophila simulans and compare them with its sibling species, D. melanogaster. We show that there are stark differences in the fitness consequences of mating with preferred males in the two species and discuss this contrast with reference to the current debates in the sexual selection literature. © 2009 Koninklijke Brill NV.
Abstract.
Birkhead TR, Hosken, D.J. Pitnick, S. (2009). Sperm Biology: an Evolutionary Perspective. , Elsevier.
Gay L, Hosken DJ, Vasudev R, Tregenza T, Eady PE (2009). Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus.
J Evol Biol,
22(5), 1143-1150.
Abstract:
Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus.
The evolutionary factors affecting testis size are well documented, with sperm competition being of major importance. However, the factors affecting sperm length are not well understood; there are no clear theoretical predictions and the empirical evidence is inconsistent. Recently, maternal effects have been implicated in sperm length variation, a finding that may offer insights into its evolution. We investigated potential proximate and microevolutionary factors influencing testis and sperm size in the bruchid beetle Callosobruchus maculatus using a combined approach of an artificial evolution experiment over 90 generations and an environmental effects study. We found that while polyandry seems to select for larger testes, it had no detectable effect on sperm length. Furthermore, population density, a proximate indicator of sperm competition risk, was not significantly associated with sperm length or testis size variation. However, there were strong maternal effects influencing sperm length.
Abstract.
Author URL.
Pitnick S, Dobler R, Hosken DJ (2009). Sperm length is not influenced by haploid gene expression in the flies Drosophila melanogaster and Scathophaga stercoraria.
Proc Biol Sci,
276(1675), 4029-4034.
Abstract:
Sperm length is not influenced by haploid gene expression in the flies Drosophila melanogaster and Scathophaga stercoraria.
Recent theoretical models have postulated a role for haploid-diploid conflict and for kin selection favouring sperm cooperation and altruism in the diversification and specialization of sperm form. A critical assumption of these models-that haploid gene expression contributes to variation in sperm form-has never been demonstrated and remains contentious. By quantifying within-male variation in sperm length using crosses between males and females from populations that had been subjected to divergent experimental selection, we demonstrate that haploid gene expression does not contribute to variation in sperm length in both Drosophila melanogaster and Scathophaga stercoraria. This finding casts doubt on the importance of haploid-diploid conflict and kin selection as evolutionary influences of sperm phenotypes.
Abstract.
Author URL.
Pitnick S, Hosken DJ, Birkhead TR (2009). Sperm morphological diversity.
, 69-149.
Abstract:
Sperm morphological diversity
This chapter reviews the current knowledge of variation in sperm morphology over several levels of biological organization: variation within males (both within and across ejaculates), among males, among populations, and among species, along with prevailing hypotheses addressing the adaptive significance of such variation. With regard to developmental mechanisms, three aspects of the physiology of sperm production serve to limit within-ejaculate variation in sperm phenotypes. First, the location of the testes and numerous aspects of testicular physiology of some taxa are clearly adaptations to maintain a homeostatic developmental environment for sperm. Second, developing spermatids may share cytoplasm. Third, sperm phenotypes are predominantly determined by testicular gene expression and hence the diploid genome of the male. Variation across ejaculates but within males can involve several traits including sperm numbers, overall semen quality and individual sperm quality. A special case of intramale variation in sperm form is found in species with sperm heteromorphism, in which different sperm forms are regularly produced by individuals. Differences among males in sperm morphology may derive from both genetic and environmental influences. Theories of condition-dependence basically posit that fitness-related traits are to a large extent dependent on an organism's underlying condition. Conclusions drawn from studies of sperm diversification between natural populations are reinforced by experimental evolution studies of sperm morphology in laboratory populations, as these studies address the evolvability of sperm traits and the nature of selection underlying sperm diversification. Furthermore, a discussion of evolutionary causes and consequences of sperm diversification, along with suggestions of fruitful areas for future exploration is presented. © 2009 Copyright © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Lessells CM, Snook RR, Hosken DJ (2009). The evolutionary origin and maintenance of sperm: Selection for a small, motile gamete mating type.
, 43-67.
Abstract:
The evolutionary origin and maintenance of sperm: Selection for a small, motile gamete mating type
Sperm have three fundamental characteristics: they are small, they are motile, and they fuse disassortatively with eggs. Isogamy is generally accepted as the ancestral state and from this starting point, there are a number of different sequences by which sperm may have evolved, with any of the three characteristics of this sexual reproductive syndrome potentially having evolved first. One of the most striking features of the egg-sperm dichotomy is the massive size dimorphism. There are three general kinds of theory to explain the evolution of gamete dimorphism: gamete competition, sperm limitation, and intracellular conflict. In extant organisms, gamete dimorphism is always associated with the occurrence of two mating types with disassortative fusion. This linkage may have evolved in one of two general ways: first, mating types may have evolved before gamete dimorphism, as supported by the near-ubiquity of mating types irrespective of whether gametes are dimorphic. The evolutionary loss of motility in eggs (and the extreme specialization for motility in sperm of most species) is generally seen as the last step in the evolution of the egg-sperm dichotomy. The evolution of motility dimorphism might also be concomitant with that of size dimorphism, or it might have evolved after both size dimorphism and mating types. © 2009 Copyright © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Smith DT, Hosken DJ, Ffrench-Constant RH, Wedell N (2009). Variation in sex peptide expression in D. melanogaster.
Genet Res (Camb),
91(4), 237-242.
Abstract:
Variation in sex peptide expression in D. melanogaster.
Male Drosophila melanogaster transfers many accessory-gland proteins to females during copulation. Sex peptide (SP) is one of these and one of its main effects is to decrease female remating propensity. To date, there has been no investigation of genetic variation in SP-gene expression levels, or if such potential variation directly influences female remating behaviour. We assessed both these possibilities and found significant variation in expression levels of the SP gene across D. melanogaster isolines. A non-linear association between SP expression levels and female remating delay suggestive of disruptive selection on expression levels was also documented. Finally, while some isolines were infected with the endosymbiont Wolbachia, no association between Wolbachia and SP expression level was found.
Abstract.
Author URL.
2008
Hosken DJ, Taylor ML, Hoyle K, Higgins S, Wedell N (2008). Attractive males have greater success in sperm competition.
Current Biology,
18(13).
Abstract:
Attractive males have greater success in sperm competition
While sexual selection is responsible for the rapid evolution of many characters [1,2], the precise relationship between pre- and post-copulatory sexual selection is unclear [3]. In some species, the two are positively associated and reinforce each other, while in others, the two bouts of selection are antagonistic and cancel each other out. Here we assessed the relationship between female preference for males and male fertilization success during sperm competition in the fly Drosophila simulans. We find that attractive males sired more offspring and also find a positive genetic correlation between male attractiveness and siring success. © 2008 Elsevier Ltd. All rights reserved.
Abstract.
Hosken DJ (2008). Clitoral variation says nothing about female orgasm. Evolution and Development, 10(4), 393-395.
Wright, L, Tregenza, T. Hosken, D.J. (2008). Inbreeding, inbreeding depression and extinction. Conservation Genetics, 9, 833-843.
Demont M, Blanckenhorn WU, Hosken DJ, Garner TWJ (2008). Molecular and quantitative genetic differentiation across Europe in yellow dung flies.
J Evol Biol,
21(6), 1492-1503.
Abstract:
Molecular and quantitative genetic differentiation across Europe in yellow dung flies.
Relating geographic variation in quantitative traits to underlying population structure is crucial for understanding processes driving population differentiation, isolation and ultimately speciation. Our study represents a comprehensive population genetic survey of the yellow dung fly Scathophaga stercoraria, an important model organism for evolutionary and ecological studies, over a broad geographic scale across Europe (10 populations from the Swiss Alps to Iceland). We simultaneously assessed differentiation in five quantitative traits (body size, development time, growth rate, proportion of diapausing individuals and duration of diapause), to compare differentiation in neutral marker loci (F(ST)) to that of quantitative traits (Q(ST)). Despite long distances and uninhabitable areas between sampled populations, population structuring was very low but significant (F(ST) = 0.007, 13 microsatellite markers; F(ST) = 0.012, three allozyme markers; F(ST) = 0.007, markers combined). However, only two populations (Iceland and Sweden) showed significant allelic differentiation to all other populations. We estimated high levels of gene flow [effective number of migrants (Nm) = 6.2], there was no isolation by distance, and no indication of past genetic bottlenecks (i.e. founder events) and associated loss of genetic diversity in any northern or island population. In contrast to the low population structure, quantitative traits were strongly genetically differentiated among populations, following latitudinal clines, suggesting that selection is responsible for life history differentiation in yellow dung flies across Europe.
Abstract.
Author URL.
Taylor ML, Wigmore C, Hodgson DJ, Wedell N, Hosken DJ (2008). Multiple mating increases female fitness in Drosophila simulans.
Animal Behaviour,
76(3), 963-970.
Abstract:
Multiple mating increases female fitness in Drosophila simulans
While polyandry is essentially ubiquitous across the animal kingdom, the net fitness consequences of multiple mating remain the subject of much debate. In some taxa the costs of multiple mating outweigh potential benefits, and large direct costs are unlikely to be compensated for by indirect benefits. Nevertheless, direct and indirect benefits potentially provide females with substantial fitness returns, and these are manifest in some species. We investigated some fitness costs and benefits of multiple mating in the fly Drosophila simulans. We compared the longevity and lifetime reproductive success of females with intermittent or continual exposure to males with those of singly mated females housed alone or housed with virgin females. We also compared the same fitness components in females mated once, twice and three times. We found no difference in the lifetime reproductive success of females housed intermittently with males and those housed continually with males, but females in these treatments produced more offspring than singly mated females (housed alone or with virgin females). However, females that were continually exposed to males died younger than females from any other treatment. We also found that females who mated more than once had higher lifetime reproductive success, and that number of matings had no influence on residual longevity. These results contrast somewhat with findings from Drosophila melanogaster, and suggest that while polyandry is beneficial for female D. simulans, male harassment can be costly. © 2008 the Association for the Study of Animal Behaviour.
Abstract.
Taylor ML, Wedell, N. Hosken, D.J. (2008). Sexual selection and female fitness in <em>Drosophila simulans</em>. Behavioral Ecology and Sociobiology, 62, 721-728.
2007
Hosken, D.J. (2007). Evolution: good males are bad females. Current Biology, 17, R168-R170.
House, CM, Hunt, J. Hosken, D.J. (2007). Evolution: lending a helping hand in sperm competition?. Current Biology, R90-R92.
Teuschl Y, Hosken, D.J. Blanckenhorn, W.U. (2007). Is reduced female survival after mating a by-product of male-male competition in the dung fly <em>Sepsis cynipsea</em>?. BMC Evolutionary Biology, 7
Champion de Crespigny, F.E. & Hosken, D.J. (2007). Sexual selection: signals to die for. Current Biology, R853-R855.
Taylor, M, Wedell, N. Hosken, D.J. (2007). The heritability of attractiveness. Current Biology, 17, R959-R960.
2006
Hosken, DJ, Tregenza, T. (2006). Evolution; Inbreeding, Multiple mating and Embryonic Aid. Current Biology, 16(6), R202-R203.
Lessells CM, Bennett ATD, Birkhead TR, Colegrave N, Dall SRX, Harvey P, Hatchwell B, Hosken DJ, et al (2006). Nothing new under the sun: social selection is part of sexual selection theory. Science, 311, 689-690.
Pizzari T, Birkhead, T.R. Blows, M.W. Brooks, R. Buchanan KL, Clutton-Brock TL, Harvey P, Hosken DJ, et al (2006). Reproductive behaviour: sexual selection remains the best explanation. Science, 311
Dall, SRX, McNamara, J.M. Wedell, N. Hosken, D.J. (2006). Sexual selection cannot be replaced by cooperative game theory (and it doesn't need replacing). Science, 311
Hodgson, DJ, Hosken, D.J. (2006). Sperm competition promotes the exploitation of rival ejaculates. Journal of Theoretical Biology, 243, 230-234.
2005
Minder, A.M. Hosken DJ, Ward, P.I. (2005). Co-evolution of male and female reproductive characters across the <em>Scathophagidae</em>. Journal of Evolutionary Biology, 18, 60-69.
Hosken DJ, Tregenza T (2005). Evolution: do bad husbands make good fathers?.
Curr Biol,
15(20), R836-R838.
Abstract:
Evolution: do bad husbands make good fathers?
Males sometimes harm their mates as they seek to maximise the number of offspring they sire. But are females really suffering or do the benefits of having sons that inherit their father's manipulative traits make up for the costs? Three recent studies provide the first hard data addressing this issue, but they differ in their conclusions.
Abstract.
Author URL.
Hosken D, Snook, R. (2005). How Important is Sexual Conflict?. American Naturalist, 165, S1-S4.
Minder, A.M. Ward, P.I. Hosken, DJ (2005). Male genital allometry in <em>Scathophagidae</em> (<em>Diptera</em>). Evolutionary Ecology, 19, 501-515.
Hosken, D.J. Tregenza, T (2005). Mate choice; Been there, done that. Current Biology, 15(23), R959-R961.
Schwartzenbach G, Hosken, D.J. Ward, P.I. (2005). Sex and immunity in the yellow dung fly <em>Scathophaga stercoraria</em>. Journal of Evolutionary Biology, 18, 455-463.
Hosken, DJ, Stockley, P. (2005). Sexual Conflict. Current Biology, 15(14), R335-R336.
Tregenza, T. Hosken DJ (2005). Sexual selection: Do bad husbands make good fathers?. Current Biology, 15(20), R836-R838.
Hosken, D.J. (2005). Would you accept advice from a believer in santa?. Nature, 433
2004
Lupold S, McElligott, A.G. Hosken, D.J. (2004). Bat genitalia; allometry, variation and good genes. Biological Journal of the Linnean Society, 83, 497-507.
Martin, OY, Hosken, D.J. (2004). Copulation reduces male but not female longevity in <em>Saltella sphondylli</em> (<em>Diptera; Sepsidae</em>). Journal of Evolutionary Biology, 17, 357-362.
Blanckenhorn WU, Hellriegel, B. Hosken, D.J. Jann, P. Altweg R, Ward PI (2004). Does testis size track expected mating success in yellow dung flies?. Functional Ecology, 18, 414-418.
Garner TWJ, Pearman, P.B. Gregory's, P.T. Tomio, G. Wischiowski SG, Hosken DJ (2004). Microsatellite markers developed from <em>Thamnophis elegans</em> and <em>Thamnophis sirtalis</em> and their utility in three species of garter snakes. Molecular Ecology Notes
Martin OY, Ward, P.I. Hosken DJ (2004). Post-copulatory sexual selection and female fitness in <em>Scathophaga stercoraria</em>. Proceedings of the Royal Society of London B, 271, 353-359.
Hosken DJ, Martin OY (2004). Reproductive consequences of population divergence through sexual conflict. Current Biology, 14(10), 906-910.
Hosken DJ, Stockley, P. (2004). Sexual selection and genital evolution. Trends in Ecology & Evolution, 19, 87-93.
Hosken DJ, Snook RR (2004). Sperm death & dumping in Drosophila. Nature, 428(6986), 939-941.
2003
Hosken DJ, Garner, T.W.J. Blanckenhorn, W.U. (2003). Asymmetry, testis and sperm size in yellow dung flies. , 17, 231-236.
Hosken DJ, Stockley, P. (2003). Benefits of polyandry; a life history perspective. Evolutionary Biology, 33, 173-194.
Martin OY, Hosken, D.J. (2003). Costs and benefits of evolving under experimentally enforced polyandry or monogamy. Evolution, 57, 2765-2772.
Hosken DJ, Pitnick, S. (2003). Do queens select sperm?. Trends in Ecology & Evolution, 18
Hosken DJ, Pitnick S (2003). Do queens select sperm? [1] (multiple letters). Trends in Ecology and Evolution, 18(3), 107-108.
Hosken, D.J. Blanckenhorn WU (2003). Heritability of three condition surrogates in the yellow dung fly. Behavioral Ecology, 14(5), 612-618.
Martin OY, Leugger, R.R. Zeltner, N. Hosken, D.J. (2003). Male age, mating probability and mating costs in the fly <em>Sepsis cynipsea</em>. Evolutionary Ecology Research, 5, 119-129.
Tregenza T, Hosken DJ, Ward PI, Wedell N (2003). Maternal effects on offspring depend on female mating pattern and offspring environment in yellow dung flies. Evolution, 57(2), 297-304.
Martin, O.Y. Born, J. Huber, F. Hosken DJ (2003). Sexual conflict in <em>Sepsis cynipsea</em>: female reluctance, fertility and mate choice. Journal of Evolutionary Biology, 16, 485-490.
Hosken, D.J. (2003). Sperm Biology; Size indeed matters. Current Biology, 13, R355-R356.
Oppliger A, Naciri-Griven, Y. Ribi, G. Hosken, D.J. (2003). Sperm length influences fertilization success during sperm competition in the snail <em>Viviparus ater</em>. Molecular Ecology, 12, 485-492.
Hosken DJ, Garner, T.W.J. Tregenza, T. Wedell N, Ward PI (2003). Superior sperm competitors sire higher quality young. Proceedings of the Royal Society of London B, 270, 1933-1938.
Hosken DJ, Martin OY (2003). The evolution of reproductive isolation through sexual conflict. Nature, 423(6943), 979-982.
2002
Martin OY, Hosken, D.J. (2002). Asymmetry and fitness in female yellow dung flies. Biological Journal of the Linnean Society, 76, 557-563.
Hosken, D.J. (2002). Culture gap; Physics still seeks its unifying theory. Nature, 419
Hosken DJ, Jones KE, Chipperfield K, Dixson A (2002). Erratum: is the bat os penis sexually selected? (Behavioral Ecology and Sociobiology (2001) 50 (450-460)). Behavioral Ecology and Sociobiology, 51(3), 302-307.
Hosken DJ, Blanckenhorn, W.U. Garner, T.W.J. (2002). Heteropopulation males have a fertilization advantage during sperm competition in the yellow dung fly (<em>Scathophaga stercoraria</em>). Proceedings of the Royal Society of London B, 269, 1701-1707.
Hosken DJ, Jones KE, Chipperfield K, Dixson A (2002). Is the bat os penis sexually selected? (vol 50, pg 450, 2001).
BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY,
51(3), 302-307.
Author URL.
Blanckenhoooorn WU, Ding, A. Ward, P.I. Meile, P. Martin OY, Hosken DJ (2002). Mating with a large male yellow dung fly: cost or benefit in terms of clutch size?. Evolutionary Ecology Research, 4, 1201-1207.
Ward PI, Wedell, N. Hosken, D.J. Tregenza T (2002). Measuring the sperm competition successes of field males of the yellow dung fly. Ecological Entomology, 27, 763-765.
Martin OY, Hosken, D.J. (2002). Strategic ejaculation in the common dung fly <em>Sepsis cynipsea</em>. Animal Behaviour, 63, 541-546.
Hosken DJ, Uhia, E. Ward, P.I. (2002). The function of female accessory reproductive gland secretion and a cost to polyandry in the yellow dung fly. Physiological Entomology, 27, 87-91.
Hosken DJ, Balloux, F. (2002). Thirty years of evolution in Darwin's finches. Trends in Ecology & Evolution, 17(10), 447-448.
2001
Hosken DJ, Ward, P.I. (2001). Experimental evidence for testis size evolution via sperm competition. Ecology Letters, 4, 10-13.
Hosken, D.J. (2001). Hidden change; cryptic evolution in flycatchers. Trends in Ecology & Evolution, 16(11).
Hosken DJ, Jones, K.E. Chipperfield, K. Dixson, A. (2001). Is the bat os penis sexually selected?. Behavioral Ecology and Sociobiology, 50, 450-460.
Hosken, D.J. (2001). Sex and death microevolutionary trade-offs between reproductive and immune investment in dung flies. Current Biology, 11(10), R379-R380.
Hosken DJ, Garner TWJ, Ward PI (2001). Sexual conflict selects for male and female reproductive characters. Current Biology, 11(7), 489-493.
Hosken, D.J. (2001). Size and fluctuating asymmetry in sexually selective traits. Animal Behaviour, 62, 603-605.
Hosken DJ, O'Shea, J.E. (2001). Sperm production and immune function in two Australian bats, <em>Chalinolobus morio</em> and <em>Nyctophilus geoffroyi</em>. Ethology Ecology & Evolution, 13, 173-180.
2000
Hosken DJ, Ward, P.I. (2000). Copula in yellow dung flies (<em>Scathophaga stercoraria</em>):\r
investigating sperm competition models by histological observation. Journal of Insect Physiology, 46, 1355-1363.
Hosken DJ, Blanckenhorn, W.U. Ward, P.I. (2000). Developmental stability in yellow dung flies (<em>scathophaga stercoraria</em>); fluctuating asymmetry heterzygosity and environmental stresses. Journal of Evolutionary Biology, 13, 919-926.
Garner TWJ, Brinkmann, H. Gerlach, G. Meyer, A. Ward PI, Sporri M, Hosken DJ (2000). Polymorphic DNA microsatellites identified in the yellow dung fly (<em>Scathophaga stercoraria</em>). Molecular Ecology, 9, 2207-2208.
Hosken, D.J. Martin, O.Y. Reim, C. (2000). The cost of copulating in the dung fly <em>Sepsis cynipsea</em>. Behavioral Ecology, 13(3), 353-358.
1999
Hosken DJ, Ward, P.I. (1999). Female accessory reproductive gland activity in the yellow dung fly <em>Scathophaga stercoraria</em> (L.). Journal of Insect Physiology, 45, 800-814.
Hosken DJ, Blanckenhorn, W.U. (1999). Female, multiple mating, inbreeding avoidance,and fitness; it is not only the magnitude of costs and benefits that counts. Behavioral Ecology, 10(4), 462-464.
Hosken DJ, Meyer, E.P. Ward, O.I. (1999). Internel female reproductive anatomy and genetal interactions during copula in the yellow dung fly, <em>Scathophaga stercoraria</em> (<em>Diptera; scathophagidar</em>). Canadian Journal of Zoology, 77, 1975-1983.
Hosken DJ, Withers, P.C. (1999). Metabolic Physiology of Euthermic and Torpid Lesser Long-Eared Bats, <em>Nyctophilus geoffroyi</em> (<em>Chiroptera; vesperitlionidae</em>). Journal of Mammalogy, 80(1), 42-52.
Hosken, D.J. (1999). Sperm displacement in yellow dung flies;a role for females. Trends in Ecology & Evolution, 14, 251-252.
1998
Oppliger A, Hosken, D.J. Ribi, G. (1998). Snail sperm production characteristics vary\r
with sperm competition risk. Proceedings of the Royal Society of London B, 265, 1527-1534.
Hosken DJ, Stockley, P. (1998). Sperm counts. Trends in Ecology & Evolution, 13, 91-92.
Hosken, D.J. (1998). Sperm fertility and skewed paternity during sperm competition in the Australian long-eared bat <em>Nyctophilus geoffroyi</em> (<em>Chiroptera; vespertilionidae</em>). Journal of Zoology (London), 245, 93-100.
Hosken, D.J. (1998). Testes mass in megachiropteran bats varies in acccordance with sperm competition theory. Behavioral Ecology and Sociobiology, 44, 169-177.
Hosken DJ, Blackberry, M.A. Stewart, T.B. Stucki, A.F. (1998). The male reproductive cycle of three species of Austalian verpertilionid bat. Journal of Zoology (London), 245, 261-270.
1997
Hosken DJ (1997). Erratum: Sperm competition in bats (Proceedings of the Royal Society of London (1997) March, 264 (385-392)). Proceedings of the Royal Society B: Biological Sciences, 264(1389).
Hosken, D.J. (1997). Reproduction and the female reproductive cycle of <em>Nyctophilus geoffroyi</em> and <em>N. major</em> from south-western Australia. Australian Journal of Zoology, 45, 489-504.
Hosken, D.J. (1997). Seasonal changes in testis mass and epididymal volume in the greater long-eared bat, <em>Nyctophilus timoriensis</em> (<em>major</em>), from the goldfields region of Western Australia. Australian Mammology, 20, 121-122.
Hosken, D.J. (1997). Sperm competition in bats. Proceedings of the Royal Society of London B, 264, 385-392.
Hosken DJ, Withers, P.C. (1997). Temperature regulation and metabolism of an Australian bat, <em>Chalinolobus gouldii</em> (<em>Chiroptera: Vespertilionidae</em>) when euthermic and torpid. Journal of Comparative Physiology B, 167, 71-80.
Hosken, D.J. (1997). Thermal biology and metabolism of the greater long-eared bat, <em>Nyctophilus major</em> (<em>timoriensis</em>) (<em>Chiroptera: Vespertilionidae</em>). Australian Journal of Zoology, 45, 145-156.
1996
Hosken DJ, O'Shea, J.E. Blackberry, M.A. (1996). Blood plasma concentrations of progesterone, sperm storage and sperm viability and fertility in Gould's wattled bat (Chalinolobus gouldii) (Chiroptera: Vespertilionidae). Journal of Reproductive Fertility, 108, 171-177.
Hosken, D.J. (1996). Roost selection by the lesser long-eared bat, <em>Nyctophilus geoffroyi</em>, and greater long-eared bat, <em>N. major</em>, (<em>Chiroptera: Vespertilionidae</em>) in Banksia woodlands. Journal of the Royal Society of Western Australia, 79, 211-216.
1994
Hosken DJ, Bailey, W.J. O'Shea, J.E. Roberts, J.D. (1994). Localisation of insect calls by the bat <em>Nyctophilus geoffroyi</em> (<em>Chiroptera: Vespertilionidae</em>): a laboratory study. Australian Journal of Zoology, 42, 177-184.
Simmons LW, Llorens, T. Schinzig, M. Hosken D, Craig M (1994). Sperm competition selects for male mate choice and protandry in the bushcricket, <em>Requena verticalis</em> (<em>Orthoptera;Tettigoniidae</em>). Animal Behaviour, 47, 117-122.
1993
Simmons LW, Craig, M. Llorens, T. Schinzig, M. Hosken D (1993). Buschcricket Spermatophores vary in accord with Sperm Competition and parental investment theory. Proceedings of the Royal Society of London B, 251(1332), 183-186.
