Sperm wars and the evolution of male fertility

Reproduction, Journal Year: 2012, Volume and Issue: 144(5), P. 519 - 534

Published: Sept. 15, 2012

Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected shape male expenditure on the ejaculate. Here, we review empirical data illustrate evolutionary consequences of competition. favors evolution increased testes size and production. In some species, males appear capable adjusting number ejaculated, depending perceived levels Selection also act form function, although evidence for this remains equivocal. Comparative studies suggest length swimming speed may increase in response selection from However, mechanisms driving pattern remain unclear. Evidence influences mixed fertilization trials performed across broad range species demonstrate inconsistent relationships between function. This ambiguity part reflect important role seminal fluid proteins (sfps) play affecting There good sfps are subject competition, recent work pointing an ability adjust their chemistry rival males. We argue future research must consider components ejaculate as functional unity. Research at genomic level will identify genes ultimately control fertility.

Language: Английский

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Sexual selection and the evolution of sperm quality

Molecular Human Reproduction, Journal Year: 2014, Volume and Issue: 20(12), P. 1180 - 1189

Published: Oct. 16, 2014

Sperm experience intense and varied selection that dramatically impacts the evolution of sperm quality. Selection acts to ensure are fertilization-competent able overcome many challenges experienced on their way towards eggs. However, simply being fertilize an egg is not enough male fertility in most species. Owing prevalence female multiple mating throughout animal kingdom, successful fertilization requires outcompete rival sperm. In addition, females can actively influence quality, storage or utilization fertility. This review provides overview how these selective forces After exploring link between traits fertility, we examine post-mating competition ejaculates influences We then describe complex genetic, social sexual interactions focusing importance seminal fluid female's reproductive tract. light complexities traits, greater use multivariate approaches incorporate male–male, sperm–sperm sperm–female study quality will enhance our understanding factors influencing Because metric success—fertilization—is same across argue information about gained from non-human animals has enormous potential further impact human

Language: Английский

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Sexual Selection and the Evolution of Egg-Sperm Interactions in Broadcast-Spawning Invertebrates

Biological Bulletin, Journal Year: 2013, Volume and Issue: 224(3), P. 166 - 183

Published: June 1, 2013

Many marine invertebrate taxa are broadcast spawners, where multiple individuals release their gametes into the water for external fertilization, often in presence of from heterospecifics. Consequently, sperm encounter considerable challenges locating and fertilizing eggs conspecific females. To overcome these challenges, many exhibit species-specific attraction toward through chemical signals released (sperm chemotaxis) gamete recognition proteins (GRPs) that mediate compatibility at fertilization. In this prospective review, we highlight selective forces, but also emphasize role sexual selection, manifested competition, cryptic female choice, evolutionary conflicts interest between sexes (sexual conflict), can play mediating action egg chemoattractants GRPs, thus individual reproductive fitness. Furthermore, explore patterns selection level phenotype, plasticity, traits) to identify putative traits targeted by species. We conclude emphasizing excellent, relatively untapped, potential broadcast-spawning invertebrates as model systems illuminate several areas research post-mating selection.

Language: Английский

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Assessing the potential for egg chemoattractants to mediate sexual selection in a broadcast spawning marine invertebrate

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2012, Volume and Issue: 279(1739), P. 2855 - 2861

Published: March 21, 2012

In numerous species, egg chemoattractants play a critical role in guiding sperm towards unfertilized eggs (sperm chemotaxis). Until now, the known functions of chemotaxis include increasing effective target size eggs, thereby promoting sperm–egg encounters, and facilitating species recognition. Here, we report that broadcast spawning mussel, Mytilus galloprovincialis , may an unforeseen sexual selection by enabling to effectively ‘choose’ between different conspecific females. initial experiment, confirmed occurs M. showing are attracted when given choice or no dichotomous chamber. We then conducted two cross-classified mating experiments, each comprising same individual males females crossed identical male × female combinations, but under experimental conditions offered ‘no-choice’ (each fertilization trial took place Petri dish involved single female) ‘choice’ female's were placed centre chamber allowed choose from females). show male-by-female interactions characterized rates both there was remarkable consistency patterns migration egg-choice experiment no-choice experiment. Thus, appear exploit chemical cues preferentially swim with which they most compatible during direct sperm-to-egg encounters. These results reveal differentially select on basis cues, thus exposing potential for mediate mate genetically partners. Given prevalence across diverse taxa, our findings have broad implications other systems.

Language: Английский

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Multivariate selection drives concordant patterns of pre- and postcopulatory sexual selection in a livebearing fish

Nature Communications, Journal Year: 2015, Volume and Issue: 6(1)

Published: Sept. 15, 2015

Abstract In many species, females mate with multiple partners, meaning that sexual selection on male traits operates across a spectrum encompasses the competition for mates (that is, before mating) and fertilizations (after mating). Despite being inextricably linked, pre- postcopulatory are typically studied independently, we know almost nothing about how this divide. Here bridge knowledge gap using livebearing fish Poecilia reticulata . We show both selective episodes, as well their covariance, explain significant component of variance in reproductive fitness. Moreover, linear nonlinear simultaneously act traits, interact to generate phenotypes similar

Language: Английский

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RELATIONSHIPS BETWEEN SPERM LENGTH AND SPEED DIFFER AMONG THREE INTERNALLY AND THREE EXTERNALLY FERTILIZING SPECIES

Evolution, Journal Year: 2013, Volume and Issue: 68(1), P. 92 - 104

Published: June 26, 2013

It is often assumed that longer sperm, by virtue of their increased swimming speed, have a fertilization advantage over shorter sperm when in competition to fertilize eggs. However, there surprisingly little evidence for positive correlation between length and speed. Here we use an approach accounts within-male variation traits examine the relationships speed across broad range species, including three internally fertilizing species externally species. Our results reveal correlations size are indeed present possibly more common than currently thought. direction which prevalent within male's ejaculate among males, were influenced mode contrasting unexpected ways. Broadly, patterns revealed with flagellum heads relative swam faster, whereas faster. We discuss these light theory contrast intraspecific observed this study macroevolutionary evolution reported elsewhere.

Language: Английский

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The evolution of expenditure on testes

Journal of Zoology, Journal Year: 2016, Volume and Issue: 298(1), P. 3 - 19

Published: Jan. 1, 2016

Abstract Evolutionary theory for expenditure on gonads attracted little attention until studies in the past 3–4 decades of allocation to male and female function hermaphrodites, relative testes size (RTS) animals with separate sexes. RTS appears have varied enormously over evolutionary time, from extremely high (over 40%) some broadcast spawners less than 1% taxa copulation internal fertilization. Reasons this wide diversity deserve attention. Sperm demand (the product per ejaculate mating rate) increases testes, is moulded by a number selective forces: sperm competition, rate limitation are identified as three typically most powerful. Trade‐offs between somatic expenditures can be complex, particularly those pre‐ post‐copulatory expenditure. Theoretical models predict that should correlate positively demand, there much evidence many competition level. The relation each predicted positive low (risk) levels, negative (intensity) levels. Sexual cascade logic suggests gonad equal two sexes soon after early evolution anisogamy, but diverge widely through reducing notably evolved advanced mobility

Language: Английский

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Chemically moderated gamete preferences predict offspring fitness in a broadcast spawning invertebrate

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2014, Volume and Issue: 281(1784), P. 20140148 - 20140148

Published: April 16, 2014

Sperm chemoattraction, where sperm locate unfertilized eggs by following a concentration gradient of egg-derived chemoattractants, has been widely documented across numerous taxa. While marine invertebrates are favoured models for understanding the underlying mechanisms evolutionary forces underpinning process remain enigmatic. Here, we show that in mussels ( Mytilus galloprovincialis ), chemically moderated gamete preferences promote assortative fertilizations between genetically compatible gametes. When offered choice egg clutches from two females, exhibited consistent but differential ‘preferences’ chemical cues secreted conspecific eggs. Critically, our data reveal shown during egg-choice trials highly predictive early embryonic viability when and same individuals mixed standard (no-choice) fertilization assays. Moreover, demonstrate experimentally separating chemoattractants eggs, swimming behaviour is differentially regulated these changes with observed patterns preferences, larval survival. Together, this integrated series experiments reveals fine-tuned to respond signals emitted different choices have measurable fitness benefits.

Language: Английский

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Tactic-specific differences in seminal fluid influence sperm performance

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2013, Volume and Issue: 280(1755), P. 20122891 - 20122891

Published: Jan. 30, 2013

Seminal fluid often makes up a large part of an ejaculate, yet most empirical and theoretical studies on sperm competition have focused how characteristics (number quality) affect fertilization success. However, seminal influences own performance may potentially influence the outcome competition, by also affecting that rivals. As consequence males be expected to allocate their investment in both relation potential level competition. Grass goby (Zosterisessor ophiocephalus) is external fertilizer with guard-sneaker mating tactics, where risk varies according tactic adopted. Here, we experimentally manipulated grass ejaculates separately combining from territorial sneaker males. While did not differ when they interacted only, sneakers increased velocity rate presence males' fluid. By contrast, had detrimental effect sperm. Sperm was unaffected employing same tactic, suggesting fluid's rival-tactic based self/non-self recognition mechanism. Our findings show cross interactions success competing investing response risk.

Language: Английский

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Diet affects ejaculate traits in a lizard with condition-dependent fertilization success

Behavioral Ecology, Journal Year: 2015, Volume and Issue: 26(6), P. 1502 - 1511

Published: Jan. 1, 2015

Sexually selected traits are often driven to costly extremes by persistent directional selection. Energy acquisition and allocation can therefore influence variation in subject both precopulatory postcopulatory sexual selection, though the later have received much less attention. We tested condition dependence of sperm morphology, count, fertilization success a promiscuous lizard (Anolis sagrei) 1) collecting samples from wild males that varied naturally body condition, 2) experimentally altering captive through dietary restriction, 3) analyzing genetic paternity data competitive mating trials between differed condition. In males, length midpiece decreased with Experimental food restriction production, head, increased midpiece, variance morphology within individuals. When restricted single copulation, on high-intake diets exhibited slight but nonsignificant advantage. Reanalysis previous experiment which high- low-condition were sequentially allowed copulate ad libitum for 1 week revealed significant bias favor high-condition males. controlling mean treatment effects proportion offspring sired phenotypes, multiple regression negative correlations head length, count. Collectively, our results suggest condition-dependent A. sagrei may be partially mediated underlying

Language: Английский

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