Sperm competition and ejaculate economics

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Год журнала: 2010, Номер 85(4), С. 897 - 934

Опубликована: Июнь 16, 2010

Sperm competition was identified in 1970 as a pervasive selective force post‐copulatory sexual selection that occurs when the ejaculates of different males compete to fertilise given set ova. Since then, sperm has been much studied both empirically and theoretically. Because often favours large ejaculates, an important challenge understand evolution strategies through which invest production economise allocation maximise reproductive success under competitive conditions. mechanisms vary greatly, depending on many factors including level competition, space constraints arena, male mating roles, female influences utilisation. Consequently, theoretical models ejaculate economics are complex varied, with apparently conflicting predictions. The goal this review is synthesise basis aiming provide empiricists categorised model assumptions We show apparent contradictions between older newer can be reconciled there considerable consensus predictions generated by models. also discuss qualitative empirical support for some these predictions, detail quantitative matches observations exist yellow dung fly. argue economic theory represents powerful heuristic explain diversity traits at multiple levels: across species, within individual males. Future progress requires greater understanding mechanisms, quantification trade‐offs numbers matings gained, further knowledge their associated costs, investigation non‐sperm effects, integration pre‐ episodes selection.

Язык: Английский

---

Sperm wars and the evolution of male fertility

Reproduction, Год журнала: 2012, Номер 144(5), С. 519 - 534

Опубликована: Сен. 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.

Язык: Английский

---

Sperm morphology and sperm velocity in passerine birds

Proceedings of the Royal Society B Biological Sciences, Год журнала: 2008, Номер 276(1659), С. 1175 - 1181

Опубликована: Дек. 23, 2008

Sperm velocity is one of the main determinants outcome sperm competition. Since vary considerably in their morphology between and within species, it seems likely that associated with velocity. Theory predicts may be increased by enlarged midpiece (energetic component) or flagellum length (kinetic component), particular ratios components, such as head size. However, associations have rarely been found empirical studies. In a comparative framework passerine birds, we tested these theoretical predictions both across wide range species single family, New World blackbirds (Icteridae). study groups, was influenced predicted direction. Consistent models, results show selection on are to concomitant evolutionary forces.

Язык: Английский

---

Sperm competition and the evolution of sperm design in mammals

BMC Evolutionary Biology, Год журнала: 2011, Номер 11(1)

Опубликована: Янв. 13, 2011

Abstract Background The influence of sperm competition upon size has been a controversial issue during the last 20 years which remains unresolved for mammals. hypothesis that, when ejaculates compete with rival males, an increase in would make more competitive because it swimming speed, generated contradictory results from both theoretical and empirical studies. In addition, debate extended to components should size: midpiece accommodate mitochondria produce energy fuel motility, or principal piece generate greater propulsion forces. Results this study we examined design mammals using much larger data set (226 species) than previous analyses, corrected phylogenetic effects by complete resolved phylogeny, robust control methods. Our show as increases, all integrated manner heads become elongated. length was found be associated enhanced velocity, adaptive trait under competition. Conclusions We conclude that played important role evolution mammals, discuss why studies have failed detect it.

Язык: Английский

---

Sexual selection and the evolution of sperm quality

Molecular Human Reproduction, Год журнала: 2014, Номер 20(12), С. 1180 - 1189

Опубликована: Окт. 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

Язык: Английский

---

Resolving variation in the reproductive tradeoff between sperm size and number

Proceedings of the National Academy of Sciences, Год журнала: 2011, Номер 108(13), С. 5325 - 5330

Опубликована: Март 14, 2011

Spermatozoa are amongst the most variable cells, and three factors thought to account for this variation in design: fertilization mode, phylogeny, postcopulatory sexual selection. In addition, it has long been assumed that a tradeoff exists between sperm size number, although selection affects both traits, empirical evidence so far elusive. Our recent theoretical model predicts nature of direct number varies with competition mechanism risk. We test these predictions using comparative approach two very different taxa mechanisms: passerine birds (mechanism: simple raffle) Drosophila fruit flies (sperm displacement). show groups, males increase their total ejaculate investment increasing risk, but whereas allocate disproportionately drosophilids size. This striking difference groups can be at least partly explained by mechanisms depending on relative female reproductive tract: large animals (passerines), numbers advantageous owing dilution inside tract, small (drosophilids), physical study provides important results. First, we provide convincing existence size–number tradeoff. Second, considering dilution, taxa.

Язык: Английский

---

Sperm number and velocity affect sperm competition success in the guppy (Poecilia reticulata)

Behavioral Ecology and Sociobiology, Год журнала: 2010, Номер 65(4), С. 813 - 821

Опубликована: Окт. 21, 2010

Язык: Английский

---

COMPARATIVE EVIDENCE FOR THE EVOLUTION OF SPERM SWIMMING SPEED BY SPERM COMPETITION AND FEMALE SPERM STORAGE DURATION IN PASSERINE BIRDS

Evolution, Год журнала: 2009, Номер 63(9), С. 2466 - 2473

Опубликована: Апрель 30, 2009

Sperm swimming speed is an important determinant of male fertility and sperm competitiveness. Despite its fundamental biological importance, the underlying evolutionary processes affecting this reproductive trait are poorly understood. Using a comparative approach in phylogenetic framework, we tested predictions that swim faster with (1) increased risk competition, (2) shorter duration female storage, (3) length. We recorded 42 North American European free-living passerine bird species, representing 35 genera 16 families. found was positively related to frequency extrapair paternity (a proxy for competition) negatively associated clutch size storage). unrelated length, although length also paternity. These results suggest not closely traits evolve independently response competition birds. Our findings emphasize significance both storage as forces driving speed.

Язык: Английский

---

How Multivariate Ejaculate Traits Determine Competitive Fertilization Success in Drosophila melanogaster

Current Biology, Год журнала: 2012, Номер 22(18), С. 1667 - 1672

Опубликована: Июль 26, 2012

Язык: Английский

---

Female reproductive tract form drives the evolution of complex sperm morphology

Proceedings of the National Academy of Sciences, Год журнала: 2012, Номер 109(12), С. 4538 - 4543

Опубликована: Фев. 7, 2012

The coevolution of female mate preferences and exaggerated male traits is a fundamental prediction many sexual selection models, but has largely defied testing due to the challenges quantifying sensory cognitive bases preferences. We overcome this difficulty by focusing on postcopulatory selection, where readily quantifiable reproductive tract structures are capable biasing paternity in favor preferred sperm morphologies thus represent proximate mechanism choice when ejaculates from multiple males overlap within tract. Here, we use phylogenetically controlled generalized least squares logistic regression test whether evolution design might have driven complex, multivariate form family aquatic beetles. results indicate that tracts undergone extensive diversification diving beetles, with remodeling size shape several organs being significantly associated changes size, head shape, gains/losses conjugation conjugate size. Further, Bayesian analyses suggest loss elongation Behavioral ultrastructural examination conjugates stored indicates anchor optimal positions for fertilization. underscore importance as an agent diversification.

Язык: Английский

---