scholarly journals Predation shapes sperm performance surfaces in guppies

2019 ◽  
Vol 286 (1905) ◽  
pp. 20190869 ◽  
Author(s):  
Alessandro Devigili ◽  
Jonathan P. Evans ◽  
John L. Fitzpatrick
Keyword(s):  
Sperm Competition ◽  
Poecilia Reticulata ◽  
Ecological Factors ◽  
Fertilization Success ◽  
Species Selection ◽  
Sperm Velocity ◽  
Multiple Traits ◽  
Statistical Tool ◽  
Performance Trait ◽  
Sperm Swimming Speed

Sperm velocity is a key determinant of competitive fertilization success in many species. Selection is therefore expected to favour the evolution of faster sperm when the level of sperm competition is high. However, several aspects can determine the direction and strength of selection acting on this key performance trait, including ecological factors that influence both sperm competition and the strength of selection acting on correlated traits that may constrain evolutionary responses in sperm velocity. Here, we determine how a key ecological variable, the level of predation, shapes sperm swimming speed across 18 Trinidadian populations of guppies ( Poecilia reticulata ). We use performance analysis, a statistical tool akin to the familiar methods of multivariate selection analyses, to determine how the level of predation influences sperm velocity (modelled as a performance trait) when accounting for correlated pre- and postcopulatory traits that are also impacted by predation. We show that predation affects the combination of pre- and postcopulatory traits that ultimately predict sperm performance. Overall, we report evidence for disruptive relationships between sperm performance and combinations of ornaments and sperm morphology, but the specific combinations of traits that predict sperm velocity depended on the level of predation. These analyses underscore the complex nonlinear interrelationships among pre- and postcopulatory traits and the importance of considering ecological factors that may ultimately change the way in which multiple traits interact to determine a trait's performance value. As such, our results are likely to be broadly applicable across systems where selection is influenced by ecological conditions.

scholarly journals Atlantic salmon eggs favour sperm in competition that have similar major histocompatibility alleles

2008 ◽  
Vol 276 (1656) ◽  
pp. 559-566 ◽  
Author(s):  
Sarah E Yeates ◽  
Sigurd Einum ◽  
Ian A Fleming ◽  
Hendrik-Jan Megens ◽  
René J.M Stet ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Sperm Competition ◽  
Fertilization Success ◽  
Class I ◽  
Egg Recognition ◽  
Major Histocompatibility ◽  
Sperm Velocity ◽  
Paired Male ◽  
Unexpected Findings

Polyandry and post-copulatory sexual selection provide opportunities for the evolution of female differential sperm selection. Here, we examined the influence of variation in major histocompatibility (MH) class I allelic composition upon sperm competition dynamics in Atlantic salmon. We ran in vitro fertilization competitions that mimicked the gametic microenvironment, and replicated a paired-male experimental design that allowed us to compare differences in sperm competition success among males when their sperm compete for eggs from females that were genetically either similar or dissimilar at the MH class I locus. Concurrently, we measured variation in spermatozoal traits that are known to influence relative fertilization success under these conditions. Contrary to the findings demonstrating mechanisms that promote MH complex heterozygosity, our results showed that males won significantly greater relative fertilization success when competing for eggs from genetically similar females at the MH class I. This result also showed covariation with the known influences of sperm velocity on relative fertilization success. We discuss these unexpected findings in relation to sperm–egg recognition and hybridization avoidance mechanisms based upon immunogenetic variation.

Reduced sperm performance in backcross hybrids between species pairs of whitefish (Coregonus clupeaformis)

2009 ◽  
Vol 87 (7) ◽  
pp. 566-572 ◽  
Author(s):  
A. R. Whiteley ◽  
K. N. Persaud ◽  
N. Derome ◽  
R. Montgomerie ◽  
L. Bernatchez
Keyword(s):  
Sperm Competition ◽  
Swimming Speed ◽  
Fertilization Success ◽  
F1 Hybrids ◽  
Coregonus Clupeaformis ◽  
External Fertilization ◽  
Isolating Mechanisms ◽  
Species Pairs ◽  
Backcross Hybrids ◽  
Sperm Swimming Speed

Previous work has demonstrated that genomic incompatibilities work together with ecologically divergent selection to promote and maintain reproductive isolation between incipient species (dwarf and normal) of lake whitefish ( Coregonus clupeaformis (Mitchill, 1818)). Whitefish spawn in groups with external fertilization, which creates conditions for strong sperm competition. In this study, we asked whether reduced sperm performance in hybrids from whitefish species-pair matings might contribute to postzygotic isolating mechanisms between these taxa. We examined two sperm traits, sperm swimming speed and flagellum length, in pure dwarf and normal whitefish and in their F1 and backcross hybrids. We observed significantly reduced sperm swimming speed in backcross but not in F1 hybrids. Sperm flagellum length was not significantly correlated with sperm swimming speed. These results demonstrate that F1 hybrids formed in nature should be capable of the same fertilization success as the parental species during sperm competition, everything else being equal. However, reduced sperm performance in the backcross generation is consistent with other evidence suggesting that genomic incompatibilities create a range of negative fitness effects in post-F1 whitefish hybrids and provides evidence for an additional postzygotic isolation mechanism involved in the incipient speciation of sympatric dwarf and normal whitefish.

scholarly journals Sperm Numbers as a Paternity Guard in a Wild Bird

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 231
Author(s):  
Melissah Rowe ◽  
Annabel van Oort ◽  
Lyanne Brouwer ◽  
Jan T. Lifjeld ◽  
Michael S. Webster ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Sperm Competition ◽  
Ecological Factors ◽  
Fertilization Success ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Sexually Selected Traits ◽  
Paternity Success ◽  
Mating Conditions ◽  
Sperm Traits

Sperm competition is thought to impose strong selection on males to produce competitive ejaculates to outcompete rival males under competitive mating conditions. Our understanding of how different sperm traits influence fertilization success, however, remains limited, especially in wild populations. Recent literature highlights the importance of incorporating multiple ejaculate traits and pre-copulatory sexually selected traits in analyses aimed at understanding how selection acts on sperm traits. However, variation in a male’s ability to gain fertilization success may also depend upon a range of social and ecological factors that determine the opportunity for mating events both within and outside of the social pair-bond. Here, we test for an effect of sperm quantity and sperm size on male reproductive success in the red-back fairy-wren (Malurus melanocephalus) while simultaneously accounting for pre-copulatory sexual selection and potential socio-ecological correlates of male mating success. We found that sperm number (i.e., cloacal protuberance volume), but not sperm morphology, was associated with reproductive success in male red-backed fairy-wrens. Most notably, males with large numbers of sperm available for copulation achieved greater within-pair paternity success. Our results suggest that males use large sperm numbers as a defensive strategy to guard within-pair paternity success in a system where there is a high risk of sperm competition and female control of copulation. Finally, our work highlights the importance of accounting for socio-ecological factors that may influence male mating opportunities when examining the role of sperm traits in determining male reproductive success.

scholarly journals The bold and the sperm: positive association between boldness and sperm number in the guppy

2019 ◽  
Vol 6 (7) ◽  
pp. 190474 ◽  
Author(s):  
Clelia Gasparini ◽  
Elizabeth M. Speechley ◽  
Giovanni Polverino
Keyword(s):  
Reproductive Success ◽  
Personality Traits ◽  
Sperm Competition ◽  
Poecilia Reticulata ◽  
Positive Association ◽  
Sperm Number ◽  
Sperm Velocity ◽  
Fitness Consequences ◽  
Competitive Success ◽  
Sperm Traits

Assessing the consequences of personality traits on reproductive success is one of the most important challenges in personality studies and critical to understand the evolutionary implications of behavioural variability among animals. Personality traits are typically associated with mating acquisition in males, and, hence, linked to variation in their reproductive success. However, in most species, sexual selection continues after mating, and sperm traits (such as sperm number and quality) become very important in determining post-mating competitive success. Here, we investigate whether variation in personality traits is associated with variation in sperm traits using the guppy ( Poecilia reticulata ), a species with high levels of sperm competition. We found a positive association between boldness and sperm number but not sperm velocity, suggesting that bolder males have increased post-copulatory success than shyer individuals. No association was found between exploration and sperm traits. Our work highlights the importance of considering post-copulatory traits when investigating fitness consequences of personality traits, especially in species with high levels of female multiple matings and hence sperm competition.

scholarly journals The role of female reproductive fluid in sperm competition

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200077 ◽  
Author(s):  
Clelia Gasparini ◽  
Andrea Pilastro ◽  
Jonathan P. Evans
Keyword(s):  
Sperm Competition ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Sperm Velocity ◽  
Theme Issue ◽  
Diverse Range ◽  
Diverse Species ◽  
Selected Functions ◽  
Sperm Traits

The role of non-gametic components of the ejaculate (seminal fluid) in fertility and sperm competitiveness is now well established. Surprisingly, however, we know far less about female reproductive fluid (FRF) in the context of sexual selection, and insights into male–FRF interactions in the context of sperm competition have only recently emerged. Despite this limited knowledge, evidence from taxonomically diverse species has revealed insights into the effects of FRF on sperm traits that have previously been implicated in studies of sperm competition. Specifically, through the differential effects of FRF on a range of sperm traits, including chemoattraction and alterations in sperm velocity, FRF has been shown to exert positive phenotypic effects on the sperm of males that are preferred as mating partners, or those from the most compatible or genetically diverse males. Despite these tantalizing insights into the putative sexually selected functions of FRF, we largely lack a mechanistic understanding of these processes. Taken together, the evidence presented here highlights the likely ubiquity of FRF-regulated biases in fertilization success across a diverse range of taxa, thus potentially elevating the importance of FRF to other non-gametic components that have so far been studied largely in males. This article is part of the theme issue ‘Fifty years of sperm competition'.

Fertilization dynamics of sperm from different male mating tactics in bluegill (Lepomis macrochirus)

2005 ◽  
Vol 83 (12) ◽  
pp. 1638-1642 ◽  
Author(s):  
Albrecht I Schulte-Hostedde ◽  
Gary Burness
Keyword(s):  
Sperm Competition ◽  
Lepomis Macrochirus ◽  
Fertilization Success ◽  
Male Mating ◽  
Motile Sperm ◽  
Mating Tactics ◽  
Sperm Activation ◽  
Competition Theory ◽  
Sperm Density ◽  
Over Time

Sperm competition results in the evolution of ejaculate characteristics such as high sperm density, high motility, and fast sperm swimming speed. A fundamental assumption of sperm competition theory is that ejaculates with high motility and fast-swimming sperm have an advantage with respect to fertilization success. We tested this assumption by studying the fertilization dynamics of alternative mating tactics (cuckolders and parentals) of male bluegill (Lepomis macrochirus Rafinesque, 1819). Sneakers (cuckolders) have faster swimming sperm and a higher proportion of motile sperm immediately following sperm activation than do parentals; however, these variables decline more quickly over time in sneaker sperm than in the sperm of parental males. We used a controlled fertilization experiment to test the prediction that parental males will have higher fertilization success than sneakers late in the sperm activation cycle because of the reduced rate of decline in ejaculate quality over time. We found that as the time from sperm activation increases parental sperm fertilizes more eggs than the sperm of sneakers. Our results support the idea that fertilization success is higher when ejaculates contain a higher proportion of either motile sperm or faster swimming sperm, all else being equal. In addition, after controlling for time from sperm activation, we found a significant bias in fertilization success toward parental males, suggesting that cryptic female choice might play a role in fertilization dynamics.

Post-Copulatory Sexual Selection

2021 ◽  
Author(s):  
Patricia L.R. Brennan ◽  
Dara N. Orbach
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Female Choice ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Female Reproductive Tract ◽  
Cryptic Female Choice ◽  
Trade Offs ◽  
Morphological Criteria

The field of post-copulatory sexual selection investigates how female and male adaptations have evolved to influence the fertilization of eggs while optimizing fitness during and after copulation, when females mate with multiple males. When females are polyandrous (one female mates with multiple males), they may optimize their mating rate and control the outcome of mating interactions to acquire direct and indirect benefits. Polyandry may also favor the evolution of male traits that offer an advantage in post-copulatory male-male sperm competition. Sperm competition occurs when the sperm, seminal fluid, and/or genitalia of one male directly impacts the outcome of fertilization success of a rival male. When a female mates with multiple males, she may use information from a number of traits to choose who will sire her offspring. This cryptic female choice (CFC) to bias paternity can be based on behavioral, physiological, and morphological criteria (e.g., copulatory courtship, volume and/or composition of seminal fluid, shape of grasping appendages). Because male fitness interests are rarely perfectly aligned with female fitness interests, sexual conflict over mating and fertilization commonly occur during copulatory and post-copulatory interactions. Post-copulatory interactions inherently involve close associations between female and male reproductive characteristics, which in many species potentially include sperm storage and sperm movement inside the female reproductive tract, and highlight the intricate coevolution between the sexes. This coevolution is also common in genital morphology. The great diversity of genitalia among species is attributed to sexual selection. The evolution of genital attributes that allow females to maintain reproductive autonomy over paternity via cryptic female choice or that prevent male manipulation and sexual control via sexually antagonistic coevolution have been well documented. Additionally, cases where genitalia evolve through intrasexual competition are well known. Another important area of study in post-copulatory sexual selection is the examination of trade-offs between investments in pre-copulatory and post-copulatory traits, since organisms have limited energetic resources to allocate to reproduction, and securing both mating and fertilization is essential for reproductive success.

scholarly journals Imminent risk of predation reduces the relative strength of postcopulatory sexual selection in the guppy

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200076
Author(s):  
Alexandra Glavaschi ◽  
Silvia Cattelan ◽  
Alessandro Grapputo ◽  
Andrea Pilastro
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Repeated Measures ◽  
Poecilia Reticulata ◽  
Male Reproductive Success ◽  
Sperm Production ◽  
Postcopulatory Sexual Selection ◽  
Repeated Measures Design ◽  
Risk Of Predation ◽  
Livebearing Fish

Fifty years of research on sperm competition has led to a very good understanding of the interspecific variation in sperm production traits. The reasons why this variation is often very large within populations have been less investigated. We suggest that the interaction between fluctuating environmental conditions and polyandry is a key phenomenon explaining such variation. We focus here on imminent predation risk (IPR). IPR impacts significantly several aspects of prey behaviour and reproduction, and it is expected to influence the operation of sexual selection before and after mating. We estimated the effect of IPR on the male opportunity for pre- and postcopulatory sexual selection in guppies ( Poecilia reticulata ), a livebearing fish where females prefer colourful males and mate multiply. We used a repeated-measures design, in which males were allowed to mate with different females either under IPR or in a predator-free condition. We found that IPR increased the total opportunity for sexual selection and reduced the relative contribution of postcopulatory sexual selection to male reproductive success. IPR is inherently variable and our results suggest that interspecific reproductive interference by predators may contribute towards maintaining the variation in sperm production within populations. This article is part of the theme issue ‘Fifty years of sperm competition'.

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