Publications by category
Journal articles
Pennell TM, Field J (2021). Split sex ratios and genetic relatedness in a primitively eusocial sweat bee.
Behavioral Ecology and Sociobiology,
75(1).
Abstract:
Split sex ratios and genetic relatedness in a primitively eusocial sweat bee
© 2020, the Author(s). Abstract: in eusocial Hymenoptera, queens and their helper offspring should favour different sex investment ratios. Queens should prefer a 1:1 investment ratio, as they are equally related to offspring of both sexes (r = 0.5). In contrast, helpers should favour an investment ratio of 3:1 towards the production of female brood. This conflict arises because helpers are more closely related to full sisters (r = 0.75) than brothers (r = 0.25). However, helpers should invest relatively more in male brood if relatedness asymmetry within their colony is reduced. This can occur due to queen replacement after colony orphaning, multiple paternity and the presence of unrelated alien helpers. We analysed an unprecedentedly large number of colonies (n = 109) from a UK population of Lasioglossum malachurum, an obligate eusocial sweat bee, to tease apart the effects of these factors on colony-level investment ratios. We found that multiple paternity, unrelated alien helpers and colony orphaning were all common. Queen-right colonies invested relatively more in females than did orphaned colonies, producing a split sex ratio. However, investment ratios did not change due to multiple paternity or the presence of alien helpers, reducing inclusive fitness pay-offs for helpers. Queen control may also have been important: helpers rarely laid male eggs, and investment in female brood was lower when queens were large relative to their helpers. Genetic relatedness between helpers and the brood that they rear was 0.43 in one year and 0.37 in another year, suggesting that ecological benefits, as well as relatedness benefits, are necessary for the maintenance of helping behaviour. Significance statement: How helping behaviour is maintained in eusocial species is a key topic in evolutionary biology. Colony-level sex investment ratio changes in response to relatedness asymmetries can dramatically influence inclusive fitness benefits for helpers in eusocial Hymenoptera. The extent to which helpers in primitively eusocial colonies can respond adaptively to different sources of variation in relatedness asymmetry is unclear. Using data from 109 colonies of the sweat bee Lasioglossum malachurum, we found that queen loss, but not multiple paternity or the presence of alien helpers, was correlated with colony sex investment ratios. Moreover, we quantified average helper-brood genetic relatedness to test whether it is higher than that predicted under solitary reproduction (r = 0.5). Values equal to and below r = 0.5 suggest that relatedness benefits alone cannot explain the maintenance of helping behaviour. Ecological benefits of group living and/or coercion must also contribute.
Abstract.
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Field J, Gonzalez-Voyer A, Boulton RA (2020). The evolution of parental care strategies in subsocial wasps.
Behavioral Ecology and Sociobiology,
74(6).
Full text.
Field JP, Couchoux C (2019). Parental manipulation of offspring size in social groups: a test using
paper wasps.
Behavioral Ecology and Sociobiology Full text.
Field JP, Parsons P, Grinsted L (2019). Partner choice correlates with fine scale kin structuring in the paper wasp Polistes dominula.
PLoS ONE Full text.
Field J, Toyoizumi H (2019). The evolution of eusociality: no risk‐return tradeoff but the ecology matters.
Ecology Letters,
23(3), 518-526.
Full text.
Field JP, Pennell TM, Holman L, Morrow EH (2018). Building a new research framework for social evolution: intralocus caste antagonism.
Biological Reviews Full text.
Field JP, Accleton C, Foster W (2018). Crozier’s effect and the acceptance of intraspecific brood parasites.
Current Biology,
28, 3267-3272.
Full text.
Davison PJ, Field J (2018). Environmental barriers to sociality in an obligate eusocial sweat bee.
Insectes Sociaux,
65(4), 549-559.
Full text.
Field JP, Davison P (2018). Limited social plasticity in the socially polymorphic sweat bee Lasioglossum calceatum.
Behavioral Ecology and Sociobiology,
72, 56-56.
Full text.
Field JP, Grinsted L (2018). Predictors of nest growth: diminishing returns for subordinates in the paper wasp Polistes dominula.
Behavioral Ecology and Sociobiology,
72, 88-88.
Full text.
Grinsted L, Field J (2017). Biological markets in cooperative breeders: quantifying outside options.
Proceedings of the Royal Society B: Biological Sciences,
284(1856), 20170904-20170904.
Abstract:
Biological markets in cooperative breeders: quantifying outside options
. A major aim in evolutionary biology is to understand altruistic help and reproductive partitioning in cooperative societies, where subordinate helpers forego reproduction to rear dominant breeders' offspring. Traditional models of cooperation in these societies typically make a key assumption: that the only alternative to staying and helping is solitary breeding, an often unfeasible task. Using large-scale field experiments on paper wasps (
. Polistes dominula
. ), we show that individuals have high-quality alternative nesting options available that offer fitness payoffs just as high as their actual chosen options, far exceeding payoffs from solitary breeding. Furthermore, joiners could not easily be replaced if they were removed experimentally, suggesting that it may be costly for dominants to reject them. Our results have implications for expected payoff distributions for cooperating individuals, and suggest that biological market theory, which incorporates partner choice and competition for partners, is necessary to understand helping behaviour in societies like that of
. P. dominula
. Traditional models are likely to overestimate the incentive to stay and help, and therefore the amount of help provided, and may underestimate the size of reproductive concession required to retain subordinates. These findings are relevant for a wide range of cooperative breeders where there is dispersal between social groups.
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Parsons PJ, Couchoux C, Horsburgh GJ, Dawson DA, Field J (2017). Identification of 24 new microsatellite loci in the sweat bee Lasioglossum malachurum (Hymenoptera: Halictidae).
BMC Res Notes,
10(1).
Abstract:
Identification of 24 new microsatellite loci in the sweat bee Lasioglossum malachurum (Hymenoptera: Halictidae).
OBJECTIVE: the objective here is to identify highly polymorphic microsatellite loci for the Palaearctic sweat bee Lasioglossum malachurum. Sweat bees (Hymenoptera: Halictidae) are widespread pollinators that exhibit an unusually large range of social behaviours from non-social, where each female nests alone, to eusocial, where a single queen reproduces while the other members of the colony help to rear her offspring. They thus represent excellent models for understanding social evolution. RESULTS: 24 new microsatellite loci were successfully optimized. When amplified across 23-40 unrelated females, the number of alleles per locus ranged from 3 to 17 and the observed heterozygosities 0.45 to 0.95. Only one locus showed evidence of significant deviation from Hardy-Weinberg equilibrium. No evidence of linkage disequilibrium was found. These 24 loci will enable researchers to gain greater understanding of colony relationships within this species, an important model for the study of eusociality. Furthermore, 22 of the same loci were also successfully amplified in L. calceatum, suggesting that these loci may be useful for investigating the ecology and evolution of sweat bees in general.
Abstract.
Author URL.
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Grinsted L, Field J (2017). Market forces influence helping behaviour in cooperatively breeding paper wasps.
Nature Communications,
8 Full text.
DAVISON PJ, FIELD J (2017). Season length, body size, and social polymorphism: size clines but not saw tooth clines in sweat bees.
Ecological Entomology,
42(6), 768-776.
Full text.
Schürch R, Accleton C, Field J (2016). Consequences of a warming climate for social organisation in sweat bees.
Behavioral Ecology and Sociobiology,
70(8), 1131-1139.
Full text.
Field J, Leadbeater E (2016). Cooperation between non-relatives in a primitively eusocial paper wasp. Polistes dominula.
Philosophical Transactions of the Royal Society B: Biological Sciences,
371(1687), 20150093-20150093.
Abstract:
Cooperation between non-relatives in a primitively eusocial paper wasp. Polistes dominula
. In cooperatively breeding vertebrates, the existence of individuals that help to raise the offspring of non-relatives is well established, but unrelated helpers are less well known in the social insects. Eusocial insect groups overwhelmingly consist of close relatives, so populations where unrelated helpers are common are intriguing. Here, we focus on
. Polistes dominula—
. the best-studied primitively eusocial wasp, and a species in which nesting with non-relatives is not only present but frequent. We address two major questions: why individuals should choose to nest with non-relatives, and why such individuals participate in the costly rearing of unrelated offspring.
. Polistes dominula
. foundresses produce more offspring of their own as subordinates than when they nest independently, providing a potential explanation for co-founding by non-relatives. There is some evidence that unrelated subordinates tailor their behaviour towards direct fitness, while the role of recognition errors in generating unrelated co-foundresses is less clear. Remarkably, the remote but potentially highly rewarding chance of inheriting the dominant position appears to strongly influence behaviour, suggesting that primitively eusocial insects may have much more in common with their social vertebrate counterparts than has commonly been thought.
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Abstract.
Green JP, Almond EJ, Williamson J, Field J (2016). Regulation of host colony activity by the social parasite Polistes semenowi. Insectes Sociaux, 63(3), 385-393.
Davison PJ, Field J (2016). Social polymorphism in the sweat bee Lasioglossum (Evylaeus) calceatum.
Insectes Sociaux,
63(2), 327-338.
Full text.
Field J, Shreeves G, Kennedy M, Brace S, Gilbert JDJ (2015). Sex-biased parental care and sexual size dimorphism in a provisioning arthropod.
Behavioral Ecology and Sociobiology,
69(12), 1897-1906.
Full text.
Donaldson L, Thompson FJ, Field J, Cant MA (2014). Do paper wasps negotiate over helping effort?.
Behavioral Ecology,
25(1), 88-94.
Abstract:
Do paper wasps negotiate over helping effort?
Recent theory and empirical studies of avian biparental systems suggest that animals resolve conflict over parental care via a process of behavioral negotiation or "rules for responding." Less is known, however, about whether negotiation over helping effort occurs in cooperatively breeding animal societies or whether behavioral negotiation requires a relatively large brain. In this study, we tested whether negotiation over help occurs in a social insect, the paper wasp Polistes dominulus, by recording individual responses to both observed and experimentally induced foraging returns by other group members. In our experiments, we manipulated food delivery to the nest in 2 ways: 1) by catching departing foragers and giving them larval food to take back to the nest and 2) by giving larval food directly to wasps on the nest, which they then fed to larvae, so increasing food delivery independently of helper effort. We found no evidence from Experiment 1 that helpers adjusted their own foraging effort according to the foraging effort of other group members. However, when food was provided directly to the nest, wasps did respond by reducing their own foraging effort. One interpretation of this result is that paper wasp helpers adjust their helping effort according to the level of offspring need rather than the work rate of other helpers. Negotiation based on indicators of demand rather than work rate is a likely mechanism to resolve conflict over investment in teams where helpers cannot observe each other's work rate directly, as is commonly the case in insect and vertebrate societies. © the Author 2013.
Abstract.
Thompson FJ, Donaldson L, Johnstone RA, Field J, Cant MA (2014). Dominant aggression as a deterrent signal in paper wasps. Behavioral Ecology, 25(4), 706-715.
Toyoizumi H, Field J (2014). Dynamics of social queues.
Journal of Theoretical Biology,
346, 16-22.
Full text.
Toyoizumi H, Field J (2014). Reduction of Foraging Work and Cooperative Breeding. Acta Biotheoretica, 62(2), 123-132.
Green JP, Cant MA, Field J (2014). Using social parasitism to test reproductive skew models in a primitively eusocial wasp.
Proceedings. Biological sciences,
281(1789).
Abstract:
Using social parasitism to test reproductive skew models in a primitively eusocial wasp.
Remarkable variation exists in the distribution of reproduction (skew) among members of cooperatively breeding groups, both within and between species. Reproductive skew theory has provided an important framework for understanding this variation. In the primitively eusocial Hymenoptera, two models have been routinely tested: concessions models, which assume complete control of reproduction by a dominant individual, and tug-of-war models, which assume on-going competition among group members over reproduction. Current data provide little support for either model, but uncertainty about the ability of individuals to detect genetic relatedness and difficulties in identifying traits conferring competitive ability mean that the relative importance of concessions versus tug-of-war remains unresolved. Here, we suggest that the use of social parasitism to generate meaningful variation in key social variables represents a valuable opportunity to explore the mechanisms underpinning reproductive skew within the social Hymenoptera. We present a direct test of concessions and tug-of-war models in the paper wasp Polistes dominulus by exploiting pronounced changes in relatedness and power structures that occur following replacement of the dominant by a congeneric social parasite. Comparisons of skew in parasitized and unparasitized colonies are consistent with a tug-of-war over reproduction within P. dominulus groups, but provide no evidence for reproductive concessions.
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Leadbeater E, Dapporto L, Turillazzi S, Field J (2013). Available kin recognition cues may explain why wasp behavior reflects relatedness to nest mates. Behavioral Ecology, 25(2), 344-351.
Lucas ER, Field J (2013). Caste determination through mating in primitively eusocial societies. Journal of Theoretical Biology, 335, 31-39.
Green JP, Leadbeater E, Carruthers JM, Rosser NS, Lucas ER, Field J (2013). Clypeal patterning in the paper wasp Polistes dominulus: no evidence of adaptive value in the wild. Behavioral Ecology, 24(3), 623-633.
Field J, Paxton R, Soro A, Craze P, Bridge C (2012). Body size, demography and foraging in a socially plastic sweat bee: a common garden experiment. Behavioral Ecology and Sociobiology, 66(5), 743-756.
Johnstone RA, Cant MA, Field J (2012). Sex-biased dispersal, haplodiploidy and the evolution of helping in social insects.
Proc Biol Sci,
279(1729), 787-793.
Abstract:
Sex-biased dispersal, haplodiploidy and the evolution of helping in social insects.
In his famous haplodiploidy hypothesis, W. D. Hamilton proposed that high sister-sister relatedness facilitates the evolution of kin-selected reproductive altruism among Hymenopteran females. Subsequent analyses, however, suggested that haplodiploidy cannot promote altruism unless altruists capitalize on relatedness asymmetries by helping to raise offspring whose sex ratio is more female-biased than the population at large. Here, we show that haplodiploidy is in fact more favourable than is diploidy to the evolution of reproductive altruism on the part of females, provided only that dispersal is male-biased (no sex-ratio bias or active kin discrimination is required). The effect is strong, and applies to the evolution both of sterile female helpers and of helping among breeding females. Moreover, a review of existing data suggests that female philopatry and non-local mating are widespread among nest-building Hymenoptera. We thus conclude that Hamilton was correct in his claim that 'family relationships in the Hymenoptera are potentially very favourable to the evolution of reproductive altruism'.
Abstract.
Author URL.
Green JP, Rose C, Field J (2012). The Role of Climatic Factors in the Expression of an Intrasexual Signal in the Paper Wasp Polistes dominulus. Ethology, 118(8), 766-774.
Lucas ER, Field J (2011). Active and effective nest defence by males in a social apoid wasp. Behavioral Ecology and Sociobiology, 65(8), 1499-1504.
Green JP, Field J (2011). Assessment between species: information gathering in usurpation contests between a paper wasp and its social parasite. Animal Behaviour, 81(6), 1263-1269.
Lucas ER, Field J (2011). Assured fitness returns in a social wasp with no worker caste.
Proceedings of the Royal Society B: Biological Sciences,
278(1720), 2991-2995.
Abstract:
Assured fitness returns in a social wasp with no worker caste
. The theory of assured fitness returns proposes that individuals nesting in groups gain fitness benefits from effort expended in brood-rearing, even if they die before the young that they have raised reach independence. These benefits, however, require that surviving nest-mates take up the task of rearing these young. It has been suggested that assured fitness returns could have favoured group nesting even at the origin of sociality (that is, in species without a dedicated worker caste). We show that experimentally orphaned brood of the apoid wasp
. Microstigmus nigrophthalmus
. continue to be provisioned by surviving adults for at least two weeks after the orphaning. This was the case for brood of both sexes. There was no evidence that naturally orphaned offspring received less food than those that still had mothers in the nest. Assured fitness returns can therefore represent a real benefit to nesting in groups, even in species without a dedicated worker caste.
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Zanette LRS, Field J (2011). Founders versus joiners: group formation in the paper wasp Polistes dominulus. Animal Behaviour, 82(4), 699-705.
Abbot P, Abe J, Alcock J, Alizon S, Alpedrinha JAC, Andersson M, Andre J-B, van Baalen M, Balloux F, Balshine S, et al (2011). Inclusive fitness theory and eusociality.
Nature,
471(7339), E1-E4.
Abstract:
Inclusive fitness theory and eusociality.
Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.
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Author URL.
Green JP, Field J (2011). Interpopulation variation in status signalling in the paper wasp Polistes dominulus. Animal Behaviour, 81(1), 205-209.
Leadbeater E, Carruthers JM, Green JP, Rosser NS, Field J (2011). Nest Inheritance is the Missing Source of Direct Fitness in a Primitively Eusocial Insect. Science, 333(6044), 874-876.
Lucas ER, Martins RP, Field J (2011). Reproductive skew is highly variable and correlated with genetic relatedness in a social apoid wasp. Behavioral Ecology, 22(2), 337-344.
Field J, Paxton RJ, Soro A, Bridge C (2010). Cryptic Plasticity Underlies a Major Evolutionary Transition. Current Biology, 20(22), 2028-2031.
Lucas ER, Martins RP, Zanette LRS, Field J (2010). Social and genetic structure in colonies of the social wasp Microstigmus nigrophthalmus. Insectes Sociaux, 58(1), 107-114.
Leadbeater E, Carruthers JM, Green JP, van Heusden J, Field J (2010). Unrelated Helpers in a Primitively Eusocial Wasp: is Helping Tailored Towards Direct Fitness?.
PLoS ONE,
5(8), e11997-e11997.
Full text.
LUCAS ER, HORSBURGH GJ, DAWSON DA, FIELD J (2009). Characterization of microsatellite loci isolated from the wasp. Microstigmus nigrophthalmus. (Hymenoptera). Molecular Ecology Resources, 9(6), 1492-1497.
Zanette L, Field J (2009). Cues, concessions, and inheritance: dominance hierarchies in the paper wasp Polistes dominulus. Behavioral Ecology, 20(4), 773-780.
Field J, Cant MA (2009). Social stability and helping in small animal societies.
Philos Trans R Soc Lond B Biol Sci,
364(1533), 3181-3189.
Abstract:
Social stability and helping in small animal societies.
In primitively eusocial societies, all individuals can potentially reproduce independently. The key fact that we focus on in this paper is that individuals in such societies instead often queue to inherit breeding positions. Queuing leads to systematic differences in expected future fitness. We first discuss the implications this has for variation in behaviour. For example, because helpers nearer to the front of the queue have more to lose, they should work less hard to rear the dominant's offspring. However, higher rankers may be more aggressive than low rankers, even if they risk injury in the process, if aggression functions to maintain or enhance queue position. Second, we discuss how queuing rules may be enforced through hidden threats that rarely have to be carried out. In fishes, rule breakers face the threat of eviction from the group. In contrast, subordinate paper wasps are not injured or evicted during escalated challenges against the dominant, perhaps because they are more valuable to the dominant. We discuss evidence that paper-wasp dominants avoid escalated conflicts by ceding reproduction to subordinates. Queuing rules appear usually to be enforced by individuals adjacent in the queue rather than by dominants. Further manipulative studies are required to reveal mechanisms underlying queue stability and to elucidate what determines queue position in the first place.
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Author URL.
Zanette LRS, Field J (2008). Genetic relatedness in early associations of Polistes dominulus : from related to unrelated helpers. Molecular Ecology, 17(11), 2590-2597.
Field J, Cant MA (2007). Direct fitness, reciprocity and helping: a perspective from primitively eusocial wasps.
Behav Processes,
76(2), 160-162.
Author URL.
Shreeves G, Field J (2007). Parental care and sexual size dimorphism in wasps and bees. Behavioral Ecology and Sociobiology, 62(5), 843-852.
Bridge C, Field J (2007). Queuing for dominance: gerontocracy and queue-jumping in the hover wasp Liostenogaster flavolineata. Behavioral Ecology and Sociobiology, 61(8), 1253-1259.
Field J, Turner E, Fayle T, Foster WA (2006). Costs of egg-laying and offspring provisioning: multifaceted parental investment in a digger wasp.
Proceedings of the Royal Society B: Biological Sciences,
274(1608), 445-451.
Abstract:
Costs of egg-laying and offspring provisioning: multifaceted parental investment in a digger wasp
. Nest-building Hymenoptera have been a major testing ground for theories of parental investment and sex allocation. Investment has usually been estimated by the likely costs of offspring provisioning, ignoring other aspects of parental care. Using three experimental treatments, we estimated the costs of egg-laying and provisioning separately under field conditions in a digger wasp
. Ammophila pubescens
. In one treatment, we increased the provisioning effort required per offspring by removing alternate prey items as they were brought to the nest. In two other treatments, we reduced parental effort by either preventing females from provisioning alternate nests or preventing them from both ovipositing and provisioning. Our results indicate that both egg-laying and provisioning represent significant costs of reproduction, expressed as differences in productivity but not survival. A trade-off-based model suggests that other components of parental care such as nest initiation may also represent significant costs. Costs of egg production and nest initiation are probably similar for male and female offspring, so that taking them into account leads to a less male-biased expected sex ratio. Mothers compensated only partially for prey removal in terms of the total provisions they gave to individual offspring.
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Abstract.
Cant MA, English S, Reeve HK, Field J (2006). Escalated conflict in a social hierarchy.
Proc Biol Sci,
273(1604), 2977-2984.
Abstract:
Escalated conflict in a social hierarchy.
Animals that live in cooperative societies form hierarchies in which dominant individuals reap disproportionate benefits from group cooperation. The stability of these societies requires subordinates to accept their inferior status rather than engage in escalated conflict with dominants over rank. Applying the logic of animal contests to these cases predicts that escalated conflict is more likely where subordinates are reproductively suppressed, where group productivity is high, relatedness is low, and where subordinates are relatively strong. We tested these four predictions in the field on co-foundress associations of the paper wasp Polistes dominulus by inducing contests over dominance rank experimentally. Subordinates with lower levels of ovarian development, and those in larger, more productive groups, were more likely to escalate in conflict with their dominant, as predicted. Neither genetic relatedness nor relative body size had significant effects on the probability of escalation. The original dominant emerged as the winner in all except one escalated contest. The results provide the first evidence that reproductive suppression of subordinates increases the threat of escalated conflict, and hence that reproductive sharing can promote stability of the dominant-subordinate relationship.
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Author URL.
Field J, Cronin A, Bridge C (2006). Future fitness and helping in social queues. Nature, 441(7090), 214-217.
Cant MA, Llop JB, Field J (2006). Individual variation in social aggression and the probability of inheritance: theory and a field test.
The American naturalist,
167(6), 837-852.
Abstract:
Individual variation in social aggression and the probability of inheritance: theory and a field test.
Recent theory suggests that much of the wide variation in individual behavior that exists within cooperative animal societies can be explained by variation in the future direct component of fitness, or the probability of inheritance. Here we develop two models to explore the effect of variation in future fitness on social aggression. The models predict that rates of aggression will be highest toward the front of the queue to inherit and will be higher in larger, more productive groups. A third prediction is that, in seasonal animals, aggression will increase as the time available to inherit the breeding position runs out. We tested these predictions using a model social species, the paper wasp Polistes dominulus. We found that rates of both aggressive "displays" (aimed at individuals of lower rank) and aggressive "tests" (aimed at individuals of higher rank) decreased down the hierarchy, as predicted by our models. The only other significant factor affecting aggression rates was date, with more aggression observed later in the season, also as predicted. Variation in future fitness due to inheritance rank is the hidden factor accounting for much of the variation in aggressiveness among apparently equivalent individuals in this species.
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Field, J. (2005). Helping effort in a dominance hierarchy. Behavioral Ecology, 16, 708-715
Field J (2005). The evolution of progressive provisioning. Behavioral Ecology, 16(4), 770-778.
Field J, Brace S (2004). Pre-social benefits of extended parental care. Nature, 428(6983), 650-652.
Shreeves G, Cant MA, Bolton A, Field J (2003). Insurance-based advantages for subordinate co-foundresses in a temperate paper wasp.
Proc Biol Sci,
270(1524), 1617-1622.
Abstract:
Insurance-based advantages for subordinate co-foundresses in a temperate paper wasp.
Recent explanations for the evolution of eusociality, focusing more on costs and benefits than relatedness, are largely untested. We validate one such model by showing that helpers in foundress groups of the paper wasp Polistes dominulus benefit from an insurance-based mechanism known as Assured Fitness Returns (AFRs). Experimental helper removals left remaining group members with more offspring than they would normally rear. Reduced groups succeeded in preserving the dead helpers' investment by rearing these extra offspring, even when helper removals occurred long before worker emergence. While helpers clearly gained from AFRs, offspring of lone foundresses failed after foundress death, so that AFRs represent a true advantage for helpers. Smaller, less valuable offspring were probably sacrificed to feed larger offspring, but reduced groups did not preferentially attract joiners or increase their foraging effort to compensate for their smaller workforce. We failed to detect a second insurance-based advantage, Survivorship Insurance, in which larger groups are less likely to fail than smaller groups. We suggest that through their use of small offspring as a food store to cope with temporary shortages, wasps may be less susceptible than vertebrates to offspring failure following the death of group members.
Abstract.
Author URL.
Shreeves G, Field J (2002). Group Size and Direct Fitness in Social Queues.
The American Naturalist,
159(1), 81-95.
Full text.
Cant MA, Field J (2001). Helping effort and future fitness in cooperation animal societies.
Proc Biol Sci,
268(1479), 1959-1964.
Abstract:
Helping effort and future fitness in cooperation animal societies.
Little attention has been paid to a conspicuous and universal feature of animal societies: the variation between individuals in helping effort. Here, we develop a multiplayer kin-selection model that assumes that subordinates face a trade-off because current investment in help reduces their own future reproductive success. The model makes two predictions: (i) subordinates will work less hard the closer they are to inheriting breeding status; and (ii) for a given dominance rank, subordinates will work less hard in larger groups. The second prediction reflects the larger pay-off from inheriting a larger group. Both predictions were tested through a field experiment on the paper wasp Polistes dominulus. First, we measured an index of helping effort among subordinates, then we removed successive dominants to reveal the inheritance ranks of the subordinates: their positions in the queue to inherit dominance. We found that both inheritance rank and group size had significant effects on helping effort, in the manner predicted by our model. The close match between our theoretical and empirical results suggests that individuals adjust their helping effort according to their expected future reproductive success. This relationship has probably remained hidden in previous studies that have focused on variation in genetic relatedness.
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Author URL.
Field J, Shreeves G, Sumner S, Casiraghi M (2000). Insurance-based advantage to helpers in a tropical hover wasp. Nature, 404(6780), 869-871.
Chapters
Field J, Cant, M.A. (2009). Reproductive skew in primitively eusocial insects: lessons for vertebrates. In Hager R, Jones CB (Eds.)
Reproductive Skew in Vertebrates, Cambridge: Cambridge University Press, 305-334.
Abstract:
Reproductive skew in primitively eusocial insects: lessons for vertebrates.
Abstract.
Publications by year
2021
Pennell TM, Field J (2021). Split sex ratios and genetic relatedness in a primitively eusocial sweat bee.
Behavioral Ecology and Sociobiology,
75(1).
Abstract:
Split sex ratios and genetic relatedness in a primitively eusocial sweat bee
© 2020, the Author(s). Abstract: in eusocial Hymenoptera, queens and their helper offspring should favour different sex investment ratios. Queens should prefer a 1:1 investment ratio, as they are equally related to offspring of both sexes (r = 0.5). In contrast, helpers should favour an investment ratio of 3:1 towards the production of female brood. This conflict arises because helpers are more closely related to full sisters (r = 0.75) than brothers (r = 0.25). However, helpers should invest relatively more in male brood if relatedness asymmetry within their colony is reduced. This can occur due to queen replacement after colony orphaning, multiple paternity and the presence of unrelated alien helpers. We analysed an unprecedentedly large number of colonies (n = 109) from a UK population of Lasioglossum malachurum, an obligate eusocial sweat bee, to tease apart the effects of these factors on colony-level investment ratios. We found that multiple paternity, unrelated alien helpers and colony orphaning were all common. Queen-right colonies invested relatively more in females than did orphaned colonies, producing a split sex ratio. However, investment ratios did not change due to multiple paternity or the presence of alien helpers, reducing inclusive fitness pay-offs for helpers. Queen control may also have been important: helpers rarely laid male eggs, and investment in female brood was lower when queens were large relative to their helpers. Genetic relatedness between helpers and the brood that they rear was 0.43 in one year and 0.37 in another year, suggesting that ecological benefits, as well as relatedness benefits, are necessary for the maintenance of helping behaviour. Significance statement: How helping behaviour is maintained in eusocial species is a key topic in evolutionary biology. Colony-level sex investment ratio changes in response to relatedness asymmetries can dramatically influence inclusive fitness benefits for helpers in eusocial Hymenoptera. The extent to which helpers in primitively eusocial colonies can respond adaptively to different sources of variation in relatedness asymmetry is unclear. Using data from 109 colonies of the sweat bee Lasioglossum malachurum, we found that queen loss, but not multiple paternity or the presence of alien helpers, was correlated with colony sex investment ratios. Moreover, we quantified average helper-brood genetic relatedness to test whether it is higher than that predicted under solitary reproduction (r = 0.5). Values equal to and below r = 0.5 suggest that relatedness benefits alone cannot explain the maintenance of helping behaviour. Ecological benefits of group living and/or coercion must also contribute.
Abstract.
Full text.
2020
Field J, Gonzalez-Voyer A, Boulton RA (2020). The evolution of parental care strategies in subsocial wasps.
Behavioral Ecology and Sociobiology,
74(6).
Full text.
2019
Field JP, Couchoux C (2019). Parental manipulation of offspring size in social groups: a test using
paper wasps.
Behavioral Ecology and Sociobiology Full text.
Field JP, Parsons P, Grinsted L (2019). Partner choice correlates with fine scale kin structuring in the paper wasp Polistes dominula.
PLoS ONE Full text.
Field J, Toyoizumi H (2019). The evolution of eusociality: no risk‐return tradeoff but the ecology matters.
Ecology Letters,
23(3), 518-526.
Full text.
2018
Field JP, Pennell TM, Holman L, Morrow EH (2018). Building a new research framework for social evolution: intralocus caste antagonism.
Biological Reviews Full text.
Field JP, Accleton C, Foster W (2018). Crozier’s effect and the acceptance of intraspecific brood parasites.
Current Biology,
28, 3267-3272.
Full text.
Davison PJ, Field J (2018). Environmental barriers to sociality in an obligate eusocial sweat bee.
Insectes Sociaux,
65(4), 549-559.
Full text.
Field JP, Davison P (2018). Limited social plasticity in the socially polymorphic sweat bee Lasioglossum calceatum.
Behavioral Ecology and Sociobiology,
72, 56-56.
Full text.
Field JP, Grinsted L (2018). Predictors of nest growth: diminishing returns for subordinates in the paper wasp Polistes dominula.
Behavioral Ecology and Sociobiology,
72, 88-88.
Full text.
2017
Grinsted L, Field J (2017). Biological markets in cooperative breeders: quantifying outside options.
Proceedings of the Royal Society B: Biological Sciences,
284(1856), 20170904-20170904.
Abstract:
Biological markets in cooperative breeders: quantifying outside options
. A major aim in evolutionary biology is to understand altruistic help and reproductive partitioning in cooperative societies, where subordinate helpers forego reproduction to rear dominant breeders' offspring. Traditional models of cooperation in these societies typically make a key assumption: that the only alternative to staying and helping is solitary breeding, an often unfeasible task. Using large-scale field experiments on paper wasps (
. Polistes dominula
. ), we show that individuals have high-quality alternative nesting options available that offer fitness payoffs just as high as their actual chosen options, far exceeding payoffs from solitary breeding. Furthermore, joiners could not easily be replaced if they were removed experimentally, suggesting that it may be costly for dominants to reject them. Our results have implications for expected payoff distributions for cooperating individuals, and suggest that biological market theory, which incorporates partner choice and competition for partners, is necessary to understand helping behaviour in societies like that of
. P. dominula
. Traditional models are likely to overestimate the incentive to stay and help, and therefore the amount of help provided, and may underestimate the size of reproductive concession required to retain subordinates. These findings are relevant for a wide range of cooperative breeders where there is dispersal between social groups.
.
Abstract.
Full text.
Parsons PJ, Couchoux C, Horsburgh GJ, Dawson DA, Field J (2017). Identification of 24 new microsatellite loci in the sweat bee Lasioglossum malachurum (Hymenoptera: Halictidae).
BMC Res Notes,
10(1).
Abstract:
Identification of 24 new microsatellite loci in the sweat bee Lasioglossum malachurum (Hymenoptera: Halictidae).
OBJECTIVE: the objective here is to identify highly polymorphic microsatellite loci for the Palaearctic sweat bee Lasioglossum malachurum. Sweat bees (Hymenoptera: Halictidae) are widespread pollinators that exhibit an unusually large range of social behaviours from non-social, where each female nests alone, to eusocial, where a single queen reproduces while the other members of the colony help to rear her offspring. They thus represent excellent models for understanding social evolution. RESULTS: 24 new microsatellite loci were successfully optimized. When amplified across 23-40 unrelated females, the number of alleles per locus ranged from 3 to 17 and the observed heterozygosities 0.45 to 0.95. Only one locus showed evidence of significant deviation from Hardy-Weinberg equilibrium. No evidence of linkage disequilibrium was found. These 24 loci will enable researchers to gain greater understanding of colony relationships within this species, an important model for the study of eusociality. Furthermore, 22 of the same loci were also successfully amplified in L. calceatum, suggesting that these loci may be useful for investigating the ecology and evolution of sweat bees in general.
Abstract.
Author URL.
Full text.
Grinsted L, Field J (2017). Market forces influence helping behaviour in cooperatively breeding paper wasps.
Nature Communications,
8 Full text.
DAVISON PJ, FIELD J (2017). Season length, body size, and social polymorphism: size clines but not saw tooth clines in sweat bees.
Ecological Entomology,
42(6), 768-776.
Full text.
2016
Schürch R, Accleton C, Field J (2016). Consequences of a warming climate for social organisation in sweat bees.
Behavioral Ecology and Sociobiology,
70(8), 1131-1139.
Full text.
Field J, Leadbeater E (2016). Cooperation between non-relatives in a primitively eusocial paper wasp. Polistes dominula.
Philosophical Transactions of the Royal Society B: Biological Sciences,
371(1687), 20150093-20150093.
Abstract:
Cooperation between non-relatives in a primitively eusocial paper wasp. Polistes dominula
. In cooperatively breeding vertebrates, the existence of individuals that help to raise the offspring of non-relatives is well established, but unrelated helpers are less well known in the social insects. Eusocial insect groups overwhelmingly consist of close relatives, so populations where unrelated helpers are common are intriguing. Here, we focus on
. Polistes dominula—
. the best-studied primitively eusocial wasp, and a species in which nesting with non-relatives is not only present but frequent. We address two major questions: why individuals should choose to nest with non-relatives, and why such individuals participate in the costly rearing of unrelated offspring.
. Polistes dominula
. foundresses produce more offspring of their own as subordinates than when they nest independently, providing a potential explanation for co-founding by non-relatives. There is some evidence that unrelated subordinates tailor their behaviour towards direct fitness, while the role of recognition errors in generating unrelated co-foundresses is less clear. Remarkably, the remote but potentially highly rewarding chance of inheriting the dominant position appears to strongly influence behaviour, suggesting that primitively eusocial insects may have much more in common with their social vertebrate counterparts than has commonly been thought.
.
Abstract.
Green JP, Almond EJ, Williamson J, Field J (2016). Regulation of host colony activity by the social parasite Polistes semenowi. Insectes Sociaux, 63(3), 385-393.
Davison PJ, Field J (2016). Social polymorphism in the sweat bee Lasioglossum (Evylaeus) calceatum.
Insectes Sociaux,
63(2), 327-338.
Full text.
2015
Field J, Shreeves G, Kennedy M, Brace S, Gilbert JDJ (2015). Sex-biased parental care and sexual size dimorphism in a provisioning arthropod.
Behavioral Ecology and Sociobiology,
69(12), 1897-1906.
Full text.
2014
Donaldson L, Thompson FJ, Field J, Cant MA (2014). Do paper wasps negotiate over helping effort?.
Behavioral Ecology,
25(1), 88-94.
Abstract:
Do paper wasps negotiate over helping effort?
Recent theory and empirical studies of avian biparental systems suggest that animals resolve conflict over parental care via a process of behavioral negotiation or "rules for responding." Less is known, however, about whether negotiation over helping effort occurs in cooperatively breeding animal societies or whether behavioral negotiation requires a relatively large brain. In this study, we tested whether negotiation over help occurs in a social insect, the paper wasp Polistes dominulus, by recording individual responses to both observed and experimentally induced foraging returns by other group members. In our experiments, we manipulated food delivery to the nest in 2 ways: 1) by catching departing foragers and giving them larval food to take back to the nest and 2) by giving larval food directly to wasps on the nest, which they then fed to larvae, so increasing food delivery independently of helper effort. We found no evidence from Experiment 1 that helpers adjusted their own foraging effort according to the foraging effort of other group members. However, when food was provided directly to the nest, wasps did respond by reducing their own foraging effort. One interpretation of this result is that paper wasp helpers adjust their helping effort according to the level of offspring need rather than the work rate of other helpers. Negotiation based on indicators of demand rather than work rate is a likely mechanism to resolve conflict over investment in teams where helpers cannot observe each other's work rate directly, as is commonly the case in insect and vertebrate societies. © the Author 2013.
Abstract.
Thompson FJ, Donaldson L, Johnstone RA, Field J, Cant MA (2014). Dominant aggression as a deterrent signal in paper wasps. Behavioral Ecology, 25(4), 706-715.
Toyoizumi H, Field J (2014). Dynamics of social queues.
Journal of Theoretical Biology,
346, 16-22.
Full text.
Toyoizumi H, Field J (2014). Reduction of Foraging Work and Cooperative Breeding. Acta Biotheoretica, 62(2), 123-132.
Green JP, Cant MA, Field J (2014). Using social parasitism to test reproductive skew models in a primitively eusocial wasp.
Proceedings. Biological sciences,
281(1789).
Abstract:
Using social parasitism to test reproductive skew models in a primitively eusocial wasp.
Remarkable variation exists in the distribution of reproduction (skew) among members of cooperatively breeding groups, both within and between species. Reproductive skew theory has provided an important framework for understanding this variation. In the primitively eusocial Hymenoptera, two models have been routinely tested: concessions models, which assume complete control of reproduction by a dominant individual, and tug-of-war models, which assume on-going competition among group members over reproduction. Current data provide little support for either model, but uncertainty about the ability of individuals to detect genetic relatedness and difficulties in identifying traits conferring competitive ability mean that the relative importance of concessions versus tug-of-war remains unresolved. Here, we suggest that the use of social parasitism to generate meaningful variation in key social variables represents a valuable opportunity to explore the mechanisms underpinning reproductive skew within the social Hymenoptera. We present a direct test of concessions and tug-of-war models in the paper wasp Polistes dominulus by exploiting pronounced changes in relatedness and power structures that occur following replacement of the dominant by a congeneric social parasite. Comparisons of skew in parasitized and unparasitized colonies are consistent with a tug-of-war over reproduction within P. dominulus groups, but provide no evidence for reproductive concessions.
Abstract.
Full text.
2013
Leadbeater E, Dapporto L, Turillazzi S, Field J (2013). Available kin recognition cues may explain why wasp behavior reflects relatedness to nest mates. Behavioral Ecology, 25(2), 344-351.
Lucas ER, Field J (2013). Caste determination through mating in primitively eusocial societies. Journal of Theoretical Biology, 335, 31-39.
Green JP, Leadbeater E, Carruthers JM, Rosser NS, Lucas ER, Field J (2013). Clypeal patterning in the paper wasp Polistes dominulus: no evidence of adaptive value in the wild. Behavioral Ecology, 24(3), 623-633.
2012
Field J, Paxton R, Soro A, Craze P, Bridge C (2012). Body size, demography and foraging in a socially plastic sweat bee: a common garden experiment. Behavioral Ecology and Sociobiology, 66(5), 743-756.
Johnstone RA, Cant MA, Field J (2012). Sex-biased dispersal, haplodiploidy and the evolution of helping in social insects.
Proc Biol Sci,
279(1729), 787-793.
Abstract:
Sex-biased dispersal, haplodiploidy and the evolution of helping in social insects.
In his famous haplodiploidy hypothesis, W. D. Hamilton proposed that high sister-sister relatedness facilitates the evolution of kin-selected reproductive altruism among Hymenopteran females. Subsequent analyses, however, suggested that haplodiploidy cannot promote altruism unless altruists capitalize on relatedness asymmetries by helping to raise offspring whose sex ratio is more female-biased than the population at large. Here, we show that haplodiploidy is in fact more favourable than is diploidy to the evolution of reproductive altruism on the part of females, provided only that dispersal is male-biased (no sex-ratio bias or active kin discrimination is required). The effect is strong, and applies to the evolution both of sterile female helpers and of helping among breeding females. Moreover, a review of existing data suggests that female philopatry and non-local mating are widespread among nest-building Hymenoptera. We thus conclude that Hamilton was correct in his claim that 'family relationships in the Hymenoptera are potentially very favourable to the evolution of reproductive altruism'.
Abstract.
Author URL.
Green JP, Rose C, Field J (2012). The Role of Climatic Factors in the Expression of an Intrasexual Signal in the Paper Wasp Polistes dominulus. Ethology, 118(8), 766-774.
2011
Lucas ER, Field J (2011). Active and effective nest defence by males in a social apoid wasp. Behavioral Ecology and Sociobiology, 65(8), 1499-1504.
Green JP, Field J (2011). Assessment between species: information gathering in usurpation contests between a paper wasp and its social parasite. Animal Behaviour, 81(6), 1263-1269.
Lucas ER, Field J (2011). Assured fitness returns in a social wasp with no worker caste.
Proceedings of the Royal Society B: Biological Sciences,
278(1720), 2991-2995.
Abstract:
Assured fitness returns in a social wasp with no worker caste
. The theory of assured fitness returns proposes that individuals nesting in groups gain fitness benefits from effort expended in brood-rearing, even if they die before the young that they have raised reach independence. These benefits, however, require that surviving nest-mates take up the task of rearing these young. It has been suggested that assured fitness returns could have favoured group nesting even at the origin of sociality (that is, in species without a dedicated worker caste). We show that experimentally orphaned brood of the apoid wasp
. Microstigmus nigrophthalmus
. continue to be provisioned by surviving adults for at least two weeks after the orphaning. This was the case for brood of both sexes. There was no evidence that naturally orphaned offspring received less food than those that still had mothers in the nest. Assured fitness returns can therefore represent a real benefit to nesting in groups, even in species without a dedicated worker caste.
.
Abstract.
Zanette LRS, Field J (2011). Founders versus joiners: group formation in the paper wasp Polistes dominulus. Animal Behaviour, 82(4), 699-705.
Abbot P, Abe J, Alcock J, Alizon S, Alpedrinha JAC, Andersson M, Andre J-B, van Baalen M, Balloux F, Balshine S, et al (2011). Inclusive fitness theory and eusociality.
Nature,
471(7339), E1-E4.
Abstract:
Inclusive fitness theory and eusociality.
Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.
Abstract.
Author URL.
Green JP, Field J (2011). Interpopulation variation in status signalling in the paper wasp Polistes dominulus. Animal Behaviour, 81(1), 205-209.
Leadbeater E, Carruthers JM, Green JP, Rosser NS, Field J (2011). Nest Inheritance is the Missing Source of Direct Fitness in a Primitively Eusocial Insect. Science, 333(6044), 874-876.
Lucas ER, Martins RP, Field J (2011). Reproductive skew is highly variable and correlated with genetic relatedness in a social apoid wasp. Behavioral Ecology, 22(2), 337-344.
2010
Field J, Paxton RJ, Soro A, Bridge C (2010). Cryptic Plasticity Underlies a Major Evolutionary Transition. Current Biology, 20(22), 2028-2031.
Lucas ER, Martins RP, Zanette LRS, Field J (2010). Social and genetic structure in colonies of the social wasp Microstigmus nigrophthalmus. Insectes Sociaux, 58(1), 107-114.
Leadbeater E, Carruthers JM, Green JP, van Heusden J, Field J (2010). Unrelated Helpers in a Primitively Eusocial Wasp: is Helping Tailored Towards Direct Fitness?.
PLoS ONE,
5(8), e11997-e11997.
Full text.
2009
LUCAS ER, HORSBURGH GJ, DAWSON DA, FIELD J (2009). Characterization of microsatellite loci isolated from the wasp. Microstigmus nigrophthalmus. (Hymenoptera). Molecular Ecology Resources, 9(6), 1492-1497.
Zanette L, Field J (2009). Cues, concessions, and inheritance: dominance hierarchies in the paper wasp Polistes dominulus. Behavioral Ecology, 20(4), 773-780.
Field J, Cant, M.A. (2009). Reproductive skew in primitively eusocial insects: lessons for vertebrates. In Hager R, Jones CB (Eds.)
Reproductive Skew in Vertebrates, Cambridge: Cambridge University Press, 305-334.
Abstract:
Reproductive skew in primitively eusocial insects: lessons for vertebrates.
Abstract.
Field J, Cant MA (2009). Social stability and helping in small animal societies.
Philos Trans R Soc Lond B Biol Sci,
364(1533), 3181-3189.
Abstract:
Social stability and helping in small animal societies.
In primitively eusocial societies, all individuals can potentially reproduce independently. The key fact that we focus on in this paper is that individuals in such societies instead often queue to inherit breeding positions. Queuing leads to systematic differences in expected future fitness. We first discuss the implications this has for variation in behaviour. For example, because helpers nearer to the front of the queue have more to lose, they should work less hard to rear the dominant's offspring. However, higher rankers may be more aggressive than low rankers, even if they risk injury in the process, if aggression functions to maintain or enhance queue position. Second, we discuss how queuing rules may be enforced through hidden threats that rarely have to be carried out. In fishes, rule breakers face the threat of eviction from the group. In contrast, subordinate paper wasps are not injured or evicted during escalated challenges against the dominant, perhaps because they are more valuable to the dominant. We discuss evidence that paper-wasp dominants avoid escalated conflicts by ceding reproduction to subordinates. Queuing rules appear usually to be enforced by individuals adjacent in the queue rather than by dominants. Further manipulative studies are required to reveal mechanisms underlying queue stability and to elucidate what determines queue position in the first place.
Abstract.
Author URL.
2008
Zanette LRS, Field J (2008). Genetic relatedness in early associations of Polistes dominulus : from related to unrelated helpers. Molecular Ecology, 17(11), 2590-2597.
2007
Field J, Cant MA (2007). Direct fitness, reciprocity and helping: a perspective from primitively eusocial wasps.
Behav Processes,
76(2), 160-162.
Author URL.
Shreeves G, Field J (2007). Parental care and sexual size dimorphism in wasps and bees. Behavioral Ecology and Sociobiology, 62(5), 843-852.
Bridge C, Field J (2007). Queuing for dominance: gerontocracy and queue-jumping in the hover wasp Liostenogaster flavolineata. Behavioral Ecology and Sociobiology, 61(8), 1253-1259.
2006
Field J, Turner E, Fayle T, Foster WA (2006). Costs of egg-laying and offspring provisioning: multifaceted parental investment in a digger wasp.
Proceedings of the Royal Society B: Biological Sciences,
274(1608), 445-451.
Abstract:
Costs of egg-laying and offspring provisioning: multifaceted parental investment in a digger wasp
. Nest-building Hymenoptera have been a major testing ground for theories of parental investment and sex allocation. Investment has usually been estimated by the likely costs of offspring provisioning, ignoring other aspects of parental care. Using three experimental treatments, we estimated the costs of egg-laying and provisioning separately under field conditions in a digger wasp
. Ammophila pubescens
. In one treatment, we increased the provisioning effort required per offspring by removing alternate prey items as they were brought to the nest. In two other treatments, we reduced parental effort by either preventing females from provisioning alternate nests or preventing them from both ovipositing and provisioning. Our results indicate that both egg-laying and provisioning represent significant costs of reproduction, expressed as differences in productivity but not survival. A trade-off-based model suggests that other components of parental care such as nest initiation may also represent significant costs. Costs of egg production and nest initiation are probably similar for male and female offspring, so that taking them into account leads to a less male-biased expected sex ratio. Mothers compensated only partially for prey removal in terms of the total provisions they gave to individual offspring.
.
Abstract.
Cant MA, English S, Reeve HK, Field J (2006). Escalated conflict in a social hierarchy.
Proc Biol Sci,
273(1604), 2977-2984.
Abstract:
Escalated conflict in a social hierarchy.
Animals that live in cooperative societies form hierarchies in which dominant individuals reap disproportionate benefits from group cooperation. The stability of these societies requires subordinates to accept their inferior status rather than engage in escalated conflict with dominants over rank. Applying the logic of animal contests to these cases predicts that escalated conflict is more likely where subordinates are reproductively suppressed, where group productivity is high, relatedness is low, and where subordinates are relatively strong. We tested these four predictions in the field on co-foundress associations of the paper wasp Polistes dominulus by inducing contests over dominance rank experimentally. Subordinates with lower levels of ovarian development, and those in larger, more productive groups, were more likely to escalate in conflict with their dominant, as predicted. Neither genetic relatedness nor relative body size had significant effects on the probability of escalation. The original dominant emerged as the winner in all except one escalated contest. The results provide the first evidence that reproductive suppression of subordinates increases the threat of escalated conflict, and hence that reproductive sharing can promote stability of the dominant-subordinate relationship.
Abstract.
Author URL.
Field J, Cronin A, Bridge C (2006). Future fitness and helping in social queues. Nature, 441(7090), 214-217.
Cant MA, Llop JB, Field J (2006). Individual variation in social aggression and the probability of inheritance: theory and a field test.
The American naturalist,
167(6), 837-852.
Abstract:
Individual variation in social aggression and the probability of inheritance: theory and a field test.
Recent theory suggests that much of the wide variation in individual behavior that exists within cooperative animal societies can be explained by variation in the future direct component of fitness, or the probability of inheritance. Here we develop two models to explore the effect of variation in future fitness on social aggression. The models predict that rates of aggression will be highest toward the front of the queue to inherit and will be higher in larger, more productive groups. A third prediction is that, in seasonal animals, aggression will increase as the time available to inherit the breeding position runs out. We tested these predictions using a model social species, the paper wasp Polistes dominulus. We found that rates of both aggressive "displays" (aimed at individuals of lower rank) and aggressive "tests" (aimed at individuals of higher rank) decreased down the hierarchy, as predicted by our models. The only other significant factor affecting aggression rates was date, with more aggression observed later in the season, also as predicted. Variation in future fitness due to inheritance rank is the hidden factor accounting for much of the variation in aggressiveness among apparently equivalent individuals in this species.
Abstract.
Full text.
2005
Field, J. (2005). Helping effort in a dominance hierarchy. Behavioral Ecology, 16, 708-715
Field J (2005). The evolution of progressive provisioning. Behavioral Ecology, 16(4), 770-778.
2004
Field J, Brace S (2004). Pre-social benefits of extended parental care. Nature, 428(6983), 650-652.
2003
Shreeves G, Cant MA, Bolton A, Field J (2003). Insurance-based advantages for subordinate co-foundresses in a temperate paper wasp.
Proc Biol Sci,
270(1524), 1617-1622.
Abstract:
Insurance-based advantages for subordinate co-foundresses in a temperate paper wasp.
Recent explanations for the evolution of eusociality, focusing more on costs and benefits than relatedness, are largely untested. We validate one such model by showing that helpers in foundress groups of the paper wasp Polistes dominulus benefit from an insurance-based mechanism known as Assured Fitness Returns (AFRs). Experimental helper removals left remaining group members with more offspring than they would normally rear. Reduced groups succeeded in preserving the dead helpers' investment by rearing these extra offspring, even when helper removals occurred long before worker emergence. While helpers clearly gained from AFRs, offspring of lone foundresses failed after foundress death, so that AFRs represent a true advantage for helpers. Smaller, less valuable offspring were probably sacrificed to feed larger offspring, but reduced groups did not preferentially attract joiners or increase their foraging effort to compensate for their smaller workforce. We failed to detect a second insurance-based advantage, Survivorship Insurance, in which larger groups are less likely to fail than smaller groups. We suggest that through their use of small offspring as a food store to cope with temporary shortages, wasps may be less susceptible than vertebrates to offspring failure following the death of group members.
Abstract.
Author URL.
2002
Shreeves G, Field J (2002). Group Size and Direct Fitness in Social Queues.
The American Naturalist,
159(1), 81-95.
Full text.
2001
Cant MA, Field J (2001). Helping effort and future fitness in cooperation animal societies.
Proc Biol Sci,
268(1479), 1959-1964.
Abstract:
Helping effort and future fitness in cooperation animal societies.
Little attention has been paid to a conspicuous and universal feature of animal societies: the variation between individuals in helping effort. Here, we develop a multiplayer kin-selection model that assumes that subordinates face a trade-off because current investment in help reduces their own future reproductive success. The model makes two predictions: (i) subordinates will work less hard the closer they are to inheriting breeding status; and (ii) for a given dominance rank, subordinates will work less hard in larger groups. The second prediction reflects the larger pay-off from inheriting a larger group. Both predictions were tested through a field experiment on the paper wasp Polistes dominulus. First, we measured an index of helping effort among subordinates, then we removed successive dominants to reveal the inheritance ranks of the subordinates: their positions in the queue to inherit dominance. We found that both inheritance rank and group size had significant effects on helping effort, in the manner predicted by our model. The close match between our theoretical and empirical results suggests that individuals adjust their helping effort according to their expected future reproductive success. This relationship has probably remained hidden in previous studies that have focused on variation in genetic relatedness.
Abstract.
Author URL.
2000
Field J, Shreeves G, Sumner S, Casiraghi M (2000). Insurance-based advantage to helpers in a tropical hover wasp. Nature, 404(6780), 869-871.
