Sperm competition and fertilization mode in fishes

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2020, Volume and Issue: 375(1813), P. 20200074 - 20200074

Published: Oct. 18, 2020

Sperm competition is a powerful selective force that has shaped sexual traits throughout animal evolution. Yet, how fertilization mode (i.e. external versus internal fertilization) influences the scope and potential for sperm to act on ejaculates remains unclear. Here, I examine shapes ejaculatory responses in fishes, diverse group constitute majority of vertebrate biological diversity. Fishes are an ideal this examination because they exhibit wide range reproductive behaviours unparalleled number transitions compared any other group. Drawing data from cartilaginous bony first show rates multiple paternity higher internally than externally fertilizing contrary prevailing expectation. then summarize acts quality highlighting where theoretical predictions differ between these groups. Differences respond modes most apparent when considering size swimming performance. Clarifying evolutionary will inform our understanding ejaculate evolution across tree life. This article part theme issue ‘Fifty years competition’.

Language: Английский

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The origins and drivers of sexual size dimorphism in sharks

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(3)

Published: March 1, 2024

Abstract While sexual size dimorphism (SSD) is abundant in nature, there huge variation both the intensity and direction of SSD. SSD results from a combination selection for large male size, fecundity female ecological either. In most vertebrates, it male–male competition that primarily underlies this study, we test four hypotheses regarding adaptive value sharks—considering potential each fecundity, sexual, reproductive mode as primary driver between species. We also estimate past macroevolutionary shifts direction/intensity through shark phylogeny. were unable to find evidence significant early sharks hypothesise derived state clade, has evolved independently observed other vertebrates. Moreover, no relationship testes mass or oceanic depth sharks. However, support previous speculation an important determinant interspecific This vertebrates thought be trends, with role clades being inconsistent at best. phylogenetic distribution among superficially similar vertebrate clades, relative importance selective pressures underlying its evolution appears differ.

Language: Английский

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The ancient and helical architecture of Elasmobranchii’s spermatozoa enables progressive motility in viscous environments

PLoS ONE, Journal Year: 2025, Volume and Issue: 20(2), P. e0319354 - e0319354

Published: Feb. 25, 2025

Subclass Elasmobranchii belongs to an old evolutionary class of Chondrichthyes that diverged 450 mya, presenting a wide diversity reproductive strategies while preserving the ancient mode internal fertilization. Despite such success, many species in this group are at serious risk extinction. Understanding principles sperm progressive motility and physiology vertebrates is crucial for advancing future assisted techniques safeguard deepening our understanding evolution reproduction. possess big spermatozoa (compared bony fishes) with elongated helical head tail similar one currently existing (but later diverged) birds, reptiles, amphibians, which can be considered ancient. These structures may associated necessity penetrate viscous ovarian fluid or jelly layer eggs, suggesting environmental viscosity as driving pressure shaping large-sized heads into shapes through evolution. We observed high-speed video microscopy capture flagellar motion three species: freshwater ray Potamotrygon motoro , marine skate Raja asterias shark Scyliorhinus canicula . investigated effect on parameters its ability break free from spermatozeugmata, move progressively, perform directional changes. After 20 min observation, spermatozeugmata conserved their structure low media 1000 mOsm/kg osmolality. In comparison, no remaining could found high-viscosity 2% methylcellulose (MC) all due motion. find spermatozoa’s unique head-to-flagellum architecture specific promote locomotion fluid; they cannot progressively viscosity. The highest velocity was 0.75% MC 1% sperm. Viscosity stabilizes propagation, producing rotational forces allowing “screw” media. Our observations suggest surrounding critical enabling control direction via newly buckling high As such, key element controlling regulating performance navigation during fertilization species.

Language: Английский

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Morphology of the male reproductive system and spermatozoa variation in Anopheles darlingi (Diptera: Culicidae)

Journal of Medical Entomology, Journal Year: 2025, Volume and Issue: unknown

Published: March 19, 2025

Abstract In this study, we present an analysis of the male reproductive system and spermatozoa Anopheles darlingi Root, 1926, primary malaria vector in Brazil. The consists a pair unifollicular testes, deferent ducts, muscular ejaculatory duct, accessory glands. average length was 188 µm, with continuous variation from 92 to 246 µm. This significant may be associated mosquito’s copulatory behavior, which females are monandrous. scenario reduce selective pressure for uniformity gametes species.

Language: Английский

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Reviewing the genetic evidence for sex-biased dispersal in elasmobranchs

Reviews in Fish Biology and Fisheries, Journal Year: 2021, Volume and Issue: 31(4), P. 821 - 841

Published: July 27, 2021

Language: Английский

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Comparative Study of Semen Parameters and Hormone Profile in Small-Spotted Catshark (Scyliorhinus canicula): Aquarium-Housed vs. Wild-Captured

Animals, Journal Year: 2021, Volume and Issue: 11(10), P. 2884 - 2884

Published: Oct. 3, 2021

Several chondrichthyan species are threatened, and we must increase our knowledge of their reproductive biology in order to establish assisted protocols for ex situ or endangered species. The small-spotted catshark (Scyliorhinus canicula) is one the most abundant shark Mediterranean coast easy maintain aquaria; therefore, it considered an ideal model. This study aimed compare S. canicula male function aquarium-housed (n = 7) wild-captured animals, recently dead 17). Aquarium-housed animals had lower semen volume (p 0.005) total sperm number 0.006) than but similar concentrations. In terms parameters, sharks showed higher motility 0.004), no differences were observed regarding viability, mitochondrial membrane potential, integrity. A morphometric pointed a significantly longer head acrosome 0.001) animals. results spermatozoa morphological consistent with previous obtained other With regard sex hormones, testosterone levels ≤ 0.001), while 17β-estradiol progesterone found. short, present provides evidence good vitro quality housed aquarium, underlining excellent potential application technologies this

Language: Английский

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Mating behavior and reproductive morphology predict macroevolution of sex allocation in hermaphroditic flatworms

BMC Biology, Journal Year: 2022, Volume and Issue: 20(1)

Published: Feb. 7, 2022

Abstract Background Sex allocation is the distribution of resources to male or female reproduction. In hermaphrodites, this concerns an individual’s resource to, for example, production gametes. Macroevolutionary studies across hermaphroditic plants have revealed that self-pollination rate and pollination mode are strong predictors sex allocation. Consequently, we expect similar factors such as selfing aspects reproductive biology, like mating behaviour intensity postcopulatory sexual selection, predict in animals. However, comparative work on animals limited. Here, study 120 species free-living flatworm genus Macrostomum . We ask how hypodermic insemination, a convergently evolved where sperm traumatically injected through partner’s epidermis, affects evolution also test commonly-made assumption investment into reproduction should trade-off. Finally, if morphological indicators selection (female genital complexity, copulatory organ length, length) can Results find repeated insemination predicts more female-biased (i.e., relative shift towards allocation). Moreover, transcriptome-based estimates heterozygosity reveal reduced hypodermically species, indicating behavior linked increased biparental inbreeding. Therefore, could represent syndrome. Furthermore, genus, gametes negatively related, larger longer sperm, male-biased Conclusions Selfing syndromes repeatedly originated plants. Remarkably, macroevolutionary pattern replicated flatworms shifts behavior. trade-off between reproduction, fundamental most theories Beyond that, no theory suggesting avenues future work. intense appear competition.

Language: Английский

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Sperm as a speciation phenotype in promiscuous songbirds

Evolution, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 1, 2024

Abstract Sperm morphology varies considerably among species. traits may contribute to speciation if they diverge fast in allopatry and cause conspecific sperm precedence upon secondary contact. However, their role driving prezygotic isolation has been poorly investigated. Here we test the hypothesis that, early process, female promiscuity promotes a reduction overlap length distributions songbird populations. We assembled data set of 20 pairs populations with known distributions, published estimate divergence time, an index derived from extrapair paternity rates or relative testis size. found that diverged more rapidly promiscuous Faster between was caused by lower variance trait species, not faster mean lengths. The reduced is presumably due stronger stabilizing selection on mediated competition. If divergent optima causes sympatry, which remains be shown empirically, promote isolation, rapid songbirds.

Language: Английский

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Unraveling Metabolite Provisioning to Offspring Through Parental Fluids: A Case Study of the Brazilian Guitarfish, Pseudobatos horkelii

Frontiers in Physiology, Journal Year: 2022, Volume and Issue: 13

Published: June 20, 2022

Elasmobranchs have a very distinct metabolism, and many aspects related to the energetic dynamics of these animals remain poorly investigated. The reproductive period is particularly vulnerable for viviparous species, as part energy reserves parental biomass reallocated gamete production embryo development. In this context, study aimed characterize metabolite provisioning offspring (both sperm developing embryos) Brazilian Guitarfish, Pseudobatos horkelii, through glucose, β-hydroxybutyrate, triglycerides, total cholesterol determinations in uterine liquid (UL) serum pregnant females seminal fluid (SF) males during copulation period. No significant difference was observed analyzed markers between UL SF. Except higher female samples, all other were present at similar concentrations both males. When comparing serum, differences triglycerides cholesterol. SF results indicate that are being made available offspring, possibly complementary yolk case maternal liquid, an additional source mobilization required egg fertilization paternal fluid. Correlations matrices also noted, compatible with metabolic pathways activated vertebrates. Moreover, marker predominance patterns noted Energy characterization directed fluids aids unraveling reproduction stage while providing support stress physiology studies evaluate indirect effects allostatic overload embryos. Finally, assessments may help elucidate how internal viviparity evolved taxonomic group.

Language: Английский

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Selection on sperm size in response to promiscuity and variation in female sperm storage organs

Journal of Evolutionary Biology, Journal Year: 2022, Volume and Issue: 36(1), P. 131 - 143

Published: Nov. 10, 2022

Abstract Sperm cells are exceptionally morphologically diverse across taxa. However, morphology can be quite uniform within species, particularly for species where females copulate with many males per reproductive bout. Strong sexual selection in these promiscuous is widely hypothesized to reduce intraspecific sperm variation. Conversely, we hypothesize that size variation may maintained by high among‐female the of storage organs, assuming paternity success improves when compatible organ. We use individual‐based simulations and an analytical model evaluate how on depends promiscuity level organ (hereafter, female preference variation). Simulations (10 mates female) showed stabilizing was low, disruptive high, consistent results. With low (2–3 female), all levels simulations, contrasting model. Promiscuity level, or mate sampling, thus has a strong impact resulting from preferences. Furthermore, male traits will occur under much more limited circumstances (i.e. only higher variation) than previous models suggest. Variation organs likely implications highly but does not explain differences less

Language: Английский

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