Publications by category
Journal articles
Tourmente M, Varea-Sánchez M, Roldan ERS (2019). Faster and more efficient swimming: Energy consumption of murine spermatozoa under sperm competition.
Biology of Reproduction,
100(2), 420-428.
Abstract:
Faster and more efficient swimming: Energy consumption of murine spermatozoa under sperm competition
© the Author(s) 2018. Published by Oxford University Press on behalf of Society for the Study of Reproduction. ATP supply is essential for sperm performance and increases in ATP content coevolve with enhanced sperm swimming velocity as a response to sperm competition in rodents. ATP content is the balance between production and consumption but, although ATP production has received much attention, little is known about ATP consumption. The rate of ATP consumption is crucial for the propagation of the flagellar wave, becoming a main determinant of the time and distance sperm could move before exhausting their reserves. A high yield in distance per unit of ATP consumed (efficiency) could provide advantages in sperm competition. We characterized sperm ATP consumption rate in a group of mouse species with different sperm competition levels to understand its impact on swimming velocity, duration, and yield of sperm ATP reserves. Interspecific comparisons revealed that sperm of species with higher sperm competition levels had high ATP consumption rates and faster swimming velocity. Moreover, sperm that consumed ATP at a faster rate swam more efficiently, since they were able to cover more distance per unit of ATP consumed. Our results suggest that by coupling the advantages of higher ATP turnover rates to increased efficiency of ATP expenditure, sperm would respond to increasingly competitive environments while maintaining a positive ATP balance.
Abstract.
Delbarco-Trillo J, Tourmente M, Varea-Sánchez M, Roldan ERS (2018). Is male reproductive senescence minimized in Mus species with high levels of sperm competition?.
Biological Journal of the Linnean Society,
123(2), 463-470.
Abstract:
Is male reproductive senescence minimized in Mus species with high levels of sperm competition?
© 2017 the Linnean Society of London. Sperm competition, an evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, gives rise to several morphological and physiological adaptations. Generally, high levels of sperm competition enhance sperm function. In contrast, advanced age is known to lead to reproductive senescence, including a general decline in sperm function. Sperm competition and advanced age may thus have opposing effects on sperm function. Here, we tested the hypothesis that the increase in sperm function in species experiencing high levels of sperm competition will counteract the negative effects of advanced age. We measured a comprehensive set of reproductive traits in young and old males in three species of mice of the genus Mus, which differ greatly in their levels of sperm competition. Our prediction was that the expression of reproductive senescence would be highest in the species with low levels of sperm competition and lowest in the species with high levels of sperm competition. Surprisingly, we did not find a strong signal of reproductive senescence in any of the three Mus species. Overall, our results did not clearly support our hypothesis that high levels of sperm competition minimize the negative effects of ageing on sperm function.
Abstract.
Tourmente M, Hirose M, Ibrahim S, Dowling DK, Tompkins DM, Roldan ERS, Gemmell NJ (2017). mtDNA polymorphism and metabolic inhibition affect sperm performance in conplastic mice.
Reproduction,
154(4), 341-354.
Abstract:
mtDNA polymorphism and metabolic inhibition affect sperm performance in conplastic mice
Whereas a broad link exists between nucleotide substitutions in the mitochondrial genome (mtDNA) and a range of metabolic pathologies, exploration of the effect of specific mtDNA genotypes is on-going. Mitochondrial DNA mutations are of particular relevance for reproductive traits, since they are expected to have profound effects on male specific processes as a result of the strict maternal inheritance of mtDNA. Sperm motility is crucially dependent on ATP in most systems studied. However, the importance of mitochondrial function in the production of the ATP necessary for sperm function remains uncertain. In this study, we test the effect of mtDNA polymorphisms upon mouse sperm performance and bioenergetics by using five conplastic inbred strains that share the same nuclear background while differing in their mitochondrial genomes. We found that, while genetic polymorphisms across distinct mtDNA haplotypes are associated with modification in sperm progressive velocity, this effect is not related to ATP production. Furthermore, there is no association between the number of mtDNA polymorphisms and either (a) the magnitude of sperm performance decrease, or (b) performance response to specific inhibition of the main sperm metabolic pathways. The observed variability between strains may be explained in terms of additive effects of single nucleotide substitutions on mtDNA coding sequences, which have been stabilized through genetic drift in the different laboratory strains. Alternatively, the decreased sperm performance might have arisen from the disruption of the nuclear DNA/mtDNA interactions that have coevolved during the radiation ofMus musculussubspecies.
Abstract.
Full text.
delBarco-Trillo J, García-Álvarez O, Soler AJ, Tourmente M, Garde JJ, Roldan ERS (2016). A cost for high levels of sperm competition in rodents: increased sperm DNA fragmentation.
Proceedings of the Royal Society B: Biological Sciences,
283(1826), 20152708-20152708.
Abstract:
A cost for high levels of sperm competition in rodents: increased sperm DNA fragmentation
Sperm competition, a prevalent evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, leads to morphological and physiological adaptations, including increases in energetic metabolism that may serve to propel sperm faster but that may have negative effects on DNA integrity. Sperm DNA damage is associated with reduced rates of fertilization, embryo and fetal loss, offspring mortality, and mutations leading to genetic disease. We tested whether high levels of sperm competition affect sperm DNA integrity. We evaluated sperm DNA integrity in 18 species of rodents that differ in their levels of sperm competition using the sperm chromatin structure assay. DNA integrity was assessed upon sperm collection, in response to incubation under capacitating or non-capacitating conditions, and after exposure to physical and chemical stressors. Sperm DNA was very resistant to physical and chemical stressors, whereas incubation in non-capacitating and capacitating conditions resulted in only a small increase in sperm DNA damage. Importantly, levels of sperm competition were positively associated with sperm DNA fragmentation across rodent species. This is the first evidence showing that high levels of sperm competition lead to an important cost in the form of increased sperm DNA damage.
Abstract.
Tourmente M, Zarka-Trigo D, Roldan ERS (2016). Is the hook of muroid rodent's sperm related to sperm train formation?. Journal of Evolutionary Biology, 29(6), 1168-1177.
Lüke L, Tourmente M, Dopazo H, Serra F, Roldan ERS (2016). Selective constraints on protamine 2 in primates and rodents. BMC Evolutionary Biology, 16(1).
Varea-Sanchez M, Tourmente M, Bastir M, Roldan ERS (2016). Unraveling the Sperm Bauplan: Relationships Between Sperm Head Morphology and Sperm Function in Rodents.
Biology of Reproduction,
95(1), 25-25.
Full text.
Tourmente M, Villar-Moya P, Rial E, Roldan ERS (2015). Differences in ATP Generation Via Glycolysis and Oxidative Phosphorylation and Relationships with Sperm Motility in Mouse Species. Journal of Biological Chemistry, 290(33), 20613-20626.
Tourmente M, Roldan ERS (2015). Mass-Specific Metabolic Rate Influences Sperm Performance through Energy Production in Mammals. PLOS ONE, 10(9), e0138185-e0138185.
Tourmente M, Delbarco Trillo J, Roldan ERS (2015). No evidence of trade-offs in the evolution of sperm numbers and sperm size in mammals. Journal of Evolutionary Biology, 28(10), 1816-1827.
Tourmente M, Villar-Moya P, Varea-Sánchez M, Luque-Larena JJ, Rial E, Roldan ERS (2015). Performance of Rodent Spermatozoa over Time is Enhanced by Increased ATP Concentrations: the Role of Sperm Competition1. Biology of Reproduction, 93(3).
Lüke L, Tourmente M, Roldan ERS (2015). Sexual Selection of Protamine 1 in Mammals. Molecular Biology and Evolution, 33(1), 174-184.
Lüke L, Vicens A, Tourmente M, Roldan ERS (2014). Evolution of Protamine Genes and Changes in Sperm Head Phenotype in Rodents1. Biology of Reproduction, 90(3).
Varea-Sánchez M, Gómez Montoto L, Tourmente M, Roldan ERS (2014). Postcopulatory Sexual Selection Results in Spermatozoa with More Uniform Head and Flagellum Sizes in Rodents. PLoS ONE, 9(9), e108148-e108148.
Vicens A, Tourmente M, Roldan ERS (2014). Structural evolution of CatSper1 in rodents is influenced by sperm competition, with effects on sperm swimming velocity. BMC Evolutionary Biology, 14(1), 106-106.
delBarco-Trillo J, Tourmente M, Roldan ERS (2013). Metabolic Rate Limits the Effect of Sperm Competition on Mammalian Spermatogenesis. PLoS ONE, 8(9), e76510-e76510.
Tourmente M, Rowe M, González-Barroso MM, Rial E, Gomendio M, Roldan ERS (2013). POSTCOPULATORY SEXUAL SELECTION INCREASES ATP CONTENT IN RODENT SPERMATOZOA. Evolution, 67(6), 1838-1846.
Tourmente M, Gomendio M, Roldan ERS (2011). Mass-Specific Metabolic Rate and Sperm Competition Determine Sperm Size in Marsupial Mammals. PLoS ONE, 6(6), e21244-e21244.
Gómez Montoto L, Magaña C, Tourmente M, Martín-Coello J, Crespo C, Luque-Larena JJ, Gomendio M, Roldan ERS (2011). Sperm Competition, Sperm Numbers and Sperm Quality in Muroid Rodents. PLoS ONE, 6(3), e18173-e18173.
Tourmente M, Giojalas LC, Chiaraviglio M (2011). Sperm Parameters Associated with Reproductive Ecology in Two Snake Species. Herpetologica, 67(1), 58-70.
Tourmente M, Gomendio M, Roldan ERS (2011). Sperm competition and the evolution of sperm design in mammals. BMC Evolutionary Biology, 11(1).
Gómez Montoto L, Varea Sánchez M, Tourmente M, Martín-Coello J, Luque-Larena JJ, Gomendio M, Roldan ERS (2011). Sperm competition differentially affects swimming velocity and size of spermatozoa from closely related muroid rodents: head first.
REPRODUCTION,
142(6), 819-830.
Abstract:
Sperm competition differentially affects swimming velocity and size of spermatozoa from closely related muroid rodents: head first
Sperm competition favours an increase in sperm swimming velocity that maximises the chances that sperm will reach the ova before rival sperm and fertilise. Comparative studies have shown that the increase in sperm swimming speed is associated with an increase in total sperm size. However, it is not known which are the first evolutionary steps that lead to increases in sperm swimming velocity. Using a group of closely related muroid rodents that differ in levels of sperm competition, we here test the hypothesis that subtle changes in sperm design may represent early evolutionary changes that could make sperm swim faster. Our findings show that as sperm competition increases so does sperm swimming speed. Sperm swimming velocity is associated with the size of all sperm components. However, levels of sperm competition are only related to an increase in sperm head area. Such increase is a consequence of an increase in the length of the sperm head, and also of the presence of an apical hook in some of the species studied. These findings suggest that the presence of a hook may modify the sperm head in such a way that would help sperm swim faster and may also be advantageous if sperm with larger heads are better able to attach to the epithelial cells lining the lower isthmus of the oviduct where sperm remain quiescent before the final race to reach the site of fertilisation.
Abstract.
Gomendio M, Tourmente M, Roldan ERS (2011). Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size.
Proceedings of the Royal Society B: Biological Sciences,
278(1721), 3135-3141.
Abstract:
Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size
The hypothesis that sperm competition should favour increases in sperm size, because it results in faster swimming speeds, has received support from studies on many taxa, but remains contentious for mammals. We suggest that this may be because mammalian lineages respond differently to sexual selection, owing to major differences in body size, which are associated with differences in mass-specific metabolic rate. Recent evidence suggests that cellular metabolic rate also scales with body size, so that small mammals have cells that process energy and resources from the environment at a faster rate. We develop the ‘metabolic rate constraint hypothesis’ which proposes that low mass-specific metabolic rate among large mammals may limit their ability to respond to sexual selection by increasing sperm size, while this constraint does not exist among small mammals. Here we show that among rodents, which have high mass-specific metabolic rates, sperm size increases under sperm competition, reaching the longest sperm sizes found in eutherian mammals. By contrast, mammalian lineages with large body sizes have small sperm, and while metabolic rate (corrected for body size) influences sperm size, sperm competition levels do not. When all eutherian mammals are analysed jointly, our results suggest that as mass-specific metabolic rate increases, so does maximum sperm size. In addition, species with low mass-specific metabolic rates produce uniformly small sperm, while species with high mass-specific metabolic rates produce a wide range of sperm sizes. These findings support the hypothesis that mass-specific metabolic rates determine the budget available for sperm production: at high levels, sperm size increases in response to sexual selection, while low levels constrain the ability to respond to sexual selection by increasing sperm size. Thus, adaptive and costly traits, such as sperm size, may only evolve under sexual selection when metabolic rate does not constrain cellular budgets.
Abstract.
Tourmente M, Gomendio M, Roldan ERS, Giojalas LC, Chiaraviglio M (2009). SPERM COMPETITION AND REPRODUCTIVE MODE INFLUENCE SPERM DIMENSIONS AND STRUCTURE AMONG SNAKES. Evolution, 63(10), 2513-2524.
Tourmente M, Giojalas L, Chiaraviglio M (2008). Sperm ultrastructure of Bothrops alternatus and Bothrops diporus (Viperidae, Serpentes), and its possible relation to the reproductive features of the species. Zoomorphology, 127(4), 241-248.
Tourmente M, Cardozo GA, Guidobaldi HA, Giojalas LC, Bertona M, Chiaraviglio M (2007). Sperm motility parameters to evaluate the seminal quality of Boa constrictor occidentalis, a threatened snake species. Research in Veterinary Science, 82(1), 93-98.
Tourmente M, Cardozo G, Bertona M, Guidobaldi A, Giojalas L, Chiaraviglio M (2006). The ultrastructure of the spermatozoa of Boa constrictor occidentalis, with considerations on its mating system and sperm competition theories. Acta Zoologica, 87(1), 25-32.
Publications by year
2019
Tourmente M, Varea-Sánchez M, Roldan ERS (2019). Faster and more efficient swimming: Energy consumption of murine spermatozoa under sperm competition.
Biology of Reproduction,
100(2), 420-428.
Abstract:
Faster and more efficient swimming: Energy consumption of murine spermatozoa under sperm competition
© the Author(s) 2018. Published by Oxford University Press on behalf of Society for the Study of Reproduction. ATP supply is essential for sperm performance and increases in ATP content coevolve with enhanced sperm swimming velocity as a response to sperm competition in rodents. ATP content is the balance between production and consumption but, although ATP production has received much attention, little is known about ATP consumption. The rate of ATP consumption is crucial for the propagation of the flagellar wave, becoming a main determinant of the time and distance sperm could move before exhausting their reserves. A high yield in distance per unit of ATP consumed (efficiency) could provide advantages in sperm competition. We characterized sperm ATP consumption rate in a group of mouse species with different sperm competition levels to understand its impact on swimming velocity, duration, and yield of sperm ATP reserves. Interspecific comparisons revealed that sperm of species with higher sperm competition levels had high ATP consumption rates and faster swimming velocity. Moreover, sperm that consumed ATP at a faster rate swam more efficiently, since they were able to cover more distance per unit of ATP consumed. Our results suggest that by coupling the advantages of higher ATP turnover rates to increased efficiency of ATP expenditure, sperm would respond to increasingly competitive environments while maintaining a positive ATP balance.
Abstract.
2018
Delbarco-Trillo J, Tourmente M, Varea-Sánchez M, Roldan ERS (2018). Is male reproductive senescence minimized in Mus species with high levels of sperm competition?.
Biological Journal of the Linnean Society,
123(2), 463-470.
Abstract:
Is male reproductive senescence minimized in Mus species with high levels of sperm competition?
© 2017 the Linnean Society of London. Sperm competition, an evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, gives rise to several morphological and physiological adaptations. Generally, high levels of sperm competition enhance sperm function. In contrast, advanced age is known to lead to reproductive senescence, including a general decline in sperm function. Sperm competition and advanced age may thus have opposing effects on sperm function. Here, we tested the hypothesis that the increase in sperm function in species experiencing high levels of sperm competition will counteract the negative effects of advanced age. We measured a comprehensive set of reproductive traits in young and old males in three species of mice of the genus Mus, which differ greatly in their levels of sperm competition. Our prediction was that the expression of reproductive senescence would be highest in the species with low levels of sperm competition and lowest in the species with high levels of sperm competition. Surprisingly, we did not find a strong signal of reproductive senescence in any of the three Mus species. Overall, our results did not clearly support our hypothesis that high levels of sperm competition minimize the negative effects of ageing on sperm function.
Abstract.
2017
Tourmente M, Hirose M, Ibrahim S, Dowling DK, Tompkins DM, Roldan ERS, Gemmell NJ (2017). mtDNA polymorphism and metabolic inhibition affect sperm performance in conplastic mice.
Reproduction,
154(4), 341-354.
Abstract:
mtDNA polymorphism and metabolic inhibition affect sperm performance in conplastic mice
Whereas a broad link exists between nucleotide substitutions in the mitochondrial genome (mtDNA) and a range of metabolic pathologies, exploration of the effect of specific mtDNA genotypes is on-going. Mitochondrial DNA mutations are of particular relevance for reproductive traits, since they are expected to have profound effects on male specific processes as a result of the strict maternal inheritance of mtDNA. Sperm motility is crucially dependent on ATP in most systems studied. However, the importance of mitochondrial function in the production of the ATP necessary for sperm function remains uncertain. In this study, we test the effect of mtDNA polymorphisms upon mouse sperm performance and bioenergetics by using five conplastic inbred strains that share the same nuclear background while differing in their mitochondrial genomes. We found that, while genetic polymorphisms across distinct mtDNA haplotypes are associated with modification in sperm progressive velocity, this effect is not related to ATP production. Furthermore, there is no association between the number of mtDNA polymorphisms and either (a) the magnitude of sperm performance decrease, or (b) performance response to specific inhibition of the main sperm metabolic pathways. The observed variability between strains may be explained in terms of additive effects of single nucleotide substitutions on mtDNA coding sequences, which have been stabilized through genetic drift in the different laboratory strains. Alternatively, the decreased sperm performance might have arisen from the disruption of the nuclear DNA/mtDNA interactions that have coevolved during the radiation ofMus musculussubspecies.
Abstract.
Full text.
2016
delBarco-Trillo J, García-Álvarez O, Soler AJ, Tourmente M, Garde JJ, Roldan ERS (2016). A cost for high levels of sperm competition in rodents: increased sperm DNA fragmentation.
Proceedings of the Royal Society B: Biological Sciences,
283(1826), 20152708-20152708.
Abstract:
A cost for high levels of sperm competition in rodents: increased sperm DNA fragmentation
Sperm competition, a prevalent evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, leads to morphological and physiological adaptations, including increases in energetic metabolism that may serve to propel sperm faster but that may have negative effects on DNA integrity. Sperm DNA damage is associated with reduced rates of fertilization, embryo and fetal loss, offspring mortality, and mutations leading to genetic disease. We tested whether high levels of sperm competition affect sperm DNA integrity. We evaluated sperm DNA integrity in 18 species of rodents that differ in their levels of sperm competition using the sperm chromatin structure assay. DNA integrity was assessed upon sperm collection, in response to incubation under capacitating or non-capacitating conditions, and after exposure to physical and chemical stressors. Sperm DNA was very resistant to physical and chemical stressors, whereas incubation in non-capacitating and capacitating conditions resulted in only a small increase in sperm DNA damage. Importantly, levels of sperm competition were positively associated with sperm DNA fragmentation across rodent species. This is the first evidence showing that high levels of sperm competition lead to an important cost in the form of increased sperm DNA damage.
Abstract.
Tourmente M, Zarka-Trigo D, Roldan ERS (2016). Is the hook of muroid rodent's sperm related to sperm train formation?. Journal of Evolutionary Biology, 29(6), 1168-1177.
Lüke L, Tourmente M, Dopazo H, Serra F, Roldan ERS (2016). Selective constraints on protamine 2 in primates and rodents. BMC Evolutionary Biology, 16(1).
Varea-Sanchez M, Tourmente M, Bastir M, Roldan ERS (2016). Unraveling the Sperm Bauplan: Relationships Between Sperm Head Morphology and Sperm Function in Rodents.
Biology of Reproduction,
95(1), 25-25.
Full text.
2015
Tourmente M, Villar-Moya P, Rial E, Roldan ERS (2015). Differences in ATP Generation Via Glycolysis and Oxidative Phosphorylation and Relationships with Sperm Motility in Mouse Species. Journal of Biological Chemistry, 290(33), 20613-20626.
Tourmente M, Roldan ERS (2015). Mass-Specific Metabolic Rate Influences Sperm Performance through Energy Production in Mammals. PLOS ONE, 10(9), e0138185-e0138185.
Tourmente M, Delbarco Trillo J, Roldan ERS (2015). No evidence of trade-offs in the evolution of sperm numbers and sperm size in mammals. Journal of Evolutionary Biology, 28(10), 1816-1827.
Tourmente M, Villar-Moya P, Varea-Sánchez M, Luque-Larena JJ, Rial E, Roldan ERS (2015). Performance of Rodent Spermatozoa over Time is Enhanced by Increased ATP Concentrations: the Role of Sperm Competition1. Biology of Reproduction, 93(3).
Lüke L, Tourmente M, Roldan ERS (2015). Sexual Selection of Protamine 1 in Mammals. Molecular Biology and Evolution, 33(1), 174-184.
2014
Lüke L, Vicens A, Tourmente M, Roldan ERS (2014). Evolution of Protamine Genes and Changes in Sperm Head Phenotype in Rodents1. Biology of Reproduction, 90(3).
Varea-Sánchez M, Gómez Montoto L, Tourmente M, Roldan ERS (2014). Postcopulatory Sexual Selection Results in Spermatozoa with More Uniform Head and Flagellum Sizes in Rodents. PLoS ONE, 9(9), e108148-e108148.
Vicens A, Tourmente M, Roldan ERS (2014). Structural evolution of CatSper1 in rodents is influenced by sperm competition, with effects on sperm swimming velocity. BMC Evolutionary Biology, 14(1), 106-106.
2013
delBarco-Trillo J, Tourmente M, Roldan ERS (2013). Metabolic Rate Limits the Effect of Sperm Competition on Mammalian Spermatogenesis. PLoS ONE, 8(9), e76510-e76510.
Tourmente M, Rowe M, González-Barroso MM, Rial E, Gomendio M, Roldan ERS (2013). POSTCOPULATORY SEXUAL SELECTION INCREASES ATP CONTENT IN RODENT SPERMATOZOA. Evolution, 67(6), 1838-1846.
2011
Tourmente M, Gomendio M, Roldan ERS (2011). Mass-Specific Metabolic Rate and Sperm Competition Determine Sperm Size in Marsupial Mammals. PLoS ONE, 6(6), e21244-e21244.
Gómez Montoto L, Magaña C, Tourmente M, Martín-Coello J, Crespo C, Luque-Larena JJ, Gomendio M, Roldan ERS (2011). Sperm Competition, Sperm Numbers and Sperm Quality in Muroid Rodents. PLoS ONE, 6(3), e18173-e18173.
Tourmente M, Giojalas LC, Chiaraviglio M (2011). Sperm Parameters Associated with Reproductive Ecology in Two Snake Species. Herpetologica, 67(1), 58-70.
Tourmente M, Gomendio M, Roldan ERS (2011). Sperm competition and the evolution of sperm design in mammals. BMC Evolutionary Biology, 11(1).
Gómez Montoto L, Varea Sánchez M, Tourmente M, Martín-Coello J, Luque-Larena JJ, Gomendio M, Roldan ERS (2011). Sperm competition differentially affects swimming velocity and size of spermatozoa from closely related muroid rodents: head first.
REPRODUCTION,
142(6), 819-830.
Abstract:
Sperm competition differentially affects swimming velocity and size of spermatozoa from closely related muroid rodents: head first
Sperm competition favours an increase in sperm swimming velocity that maximises the chances that sperm will reach the ova before rival sperm and fertilise. Comparative studies have shown that the increase in sperm swimming speed is associated with an increase in total sperm size. However, it is not known which are the first evolutionary steps that lead to increases in sperm swimming velocity. Using a group of closely related muroid rodents that differ in levels of sperm competition, we here test the hypothesis that subtle changes in sperm design may represent early evolutionary changes that could make sperm swim faster. Our findings show that as sperm competition increases so does sperm swimming speed. Sperm swimming velocity is associated with the size of all sperm components. However, levels of sperm competition are only related to an increase in sperm head area. Such increase is a consequence of an increase in the length of the sperm head, and also of the presence of an apical hook in some of the species studied. These findings suggest that the presence of a hook may modify the sperm head in such a way that would help sperm swim faster and may also be advantageous if sperm with larger heads are better able to attach to the epithelial cells lining the lower isthmus of the oviduct where sperm remain quiescent before the final race to reach the site of fertilisation.
Abstract.
Gomendio M, Tourmente M, Roldan ERS (2011). Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size.
Proceedings of the Royal Society B: Biological Sciences,
278(1721), 3135-3141.
Abstract:
Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size
The hypothesis that sperm competition should favour increases in sperm size, because it results in faster swimming speeds, has received support from studies on many taxa, but remains contentious for mammals. We suggest that this may be because mammalian lineages respond differently to sexual selection, owing to major differences in body size, which are associated with differences in mass-specific metabolic rate. Recent evidence suggests that cellular metabolic rate also scales with body size, so that small mammals have cells that process energy and resources from the environment at a faster rate. We develop the ‘metabolic rate constraint hypothesis’ which proposes that low mass-specific metabolic rate among large mammals may limit their ability to respond to sexual selection by increasing sperm size, while this constraint does not exist among small mammals. Here we show that among rodents, which have high mass-specific metabolic rates, sperm size increases under sperm competition, reaching the longest sperm sizes found in eutherian mammals. By contrast, mammalian lineages with large body sizes have small sperm, and while metabolic rate (corrected for body size) influences sperm size, sperm competition levels do not. When all eutherian mammals are analysed jointly, our results suggest that as mass-specific metabolic rate increases, so does maximum sperm size. In addition, species with low mass-specific metabolic rates produce uniformly small sperm, while species with high mass-specific metabolic rates produce a wide range of sperm sizes. These findings support the hypothesis that mass-specific metabolic rates determine the budget available for sperm production: at high levels, sperm size increases in response to sexual selection, while low levels constrain the ability to respond to sexual selection by increasing sperm size. Thus, adaptive and costly traits, such as sperm size, may only evolve under sexual selection when metabolic rate does not constrain cellular budgets.
Abstract.
2009
Tourmente M, Gomendio M, Roldan ERS, Giojalas LC, Chiaraviglio M (2009). SPERM COMPETITION AND REPRODUCTIVE MODE INFLUENCE SPERM DIMENSIONS AND STRUCTURE AMONG SNAKES. Evolution, 63(10), 2513-2524.
2008
Tourmente M, Giojalas L, Chiaraviglio M (2008). Sperm ultrastructure of Bothrops alternatus and Bothrops diporus (Viperidae, Serpentes), and its possible relation to the reproductive features of the species. Zoomorphology, 127(4), 241-248.
2007
Tourmente M, Cardozo GA, Guidobaldi HA, Giojalas LC, Bertona M, Chiaraviglio M (2007). Sperm motility parameters to evaluate the seminal quality of Boa constrictor occidentalis, a threatened snake species. Research in Veterinary Science, 82(1), 93-98.
2006
Tourmente M, Cardozo G, Bertona M, Guidobaldi A, Giojalas L, Chiaraviglio M (2006). The ultrastructure of the spermatozoa of Boa constrictor occidentalis, with considerations on its mating system and sperm competition theories. Acta Zoologica, 87(1), 25-32.