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 Bolder guppies do not have more mating partners, yet sire more offspring

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Magdalena Herdegen-Radwan
Keyword(s):  
Reproductive Success ◽  
Personality Traits ◽  
Personality Trait ◽  
Poecilia Reticulata ◽  
Direct Evidence ◽  
Animal Groups ◽  
Fitness Consequences

Abstract Background Intra-individual stable but inter-individually variable behaviours, i.e. personalities, are commonly reported across diverse animal groups, yet the reasons for their maintenance remain controversial. Therefore, studying fitness consequences of personality traits is necessary to discriminate between alternative explanations. Results Here, I measured boldness, a highly repeatable personality trait, and reproductive success in male guppies, Poecilia reticulata. I found that bolder males had higher reproductive success than their shyer conspecifics and they sired offspring with females who had larger clutches. Conclusions This result provides direct evidence for fitness consequences of boldness in the guppy. It suggests that the effect may be driven by bolder males mating with more fecund females.

scholarly journals Effect of male age on sperm traits and sperm competition success in the guppy (Poecilia reticulata)

2010 ◽  
Vol 23 (1) ◽  
pp. 124-135 ◽  
Author(s):  
C. GASPARINI ◽  
I. A. M. MARINO ◽  
C. BOSCHETTO ◽  
A. PILASTRO
Keyword(s):  
Sperm Competition ◽  
Poecilia Reticulata ◽  
Male Age ◽  
Sperm Traits

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

2010 ◽  
Vol 65 (4) ◽  
pp. 813-821 ◽  
Author(s):  
Chiara Boschetto ◽  
Clelia Gasparini ◽  
Andrea Pilastro
Keyword(s):  
Sperm Competition ◽  
Poecilia Reticulata ◽  
Sperm Number

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 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 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'.

scholarly journals Female major histocompatibility complex type affects male testosterone levels and sperm number in the horse ( Equus caballus )

2015 ◽  
Vol 282 (1807) ◽  
pp. 20150407 ◽  
Author(s):  
D. Burger ◽  
G. Dolivo ◽  
E. Marti ◽  
H. Sieme ◽  
C. Wedekind
Keyword(s):  
Major Histocompatibility Complex ◽  
Reproductive Strategies ◽  
Kin Recognition ◽  
Equus Caballus ◽  
Major Histocompatibility ◽  
Sperm Number ◽  
Sperm Velocity ◽  
Testosterone Levels ◽  
Histocompatibility Complex ◽  
Male Reproductive Strategies

Odours of vertebrates often contain information about the major histocompatibility complex (MHC), and are used in kin recognition, mate choice or female investment in pregnancy. It is, however, still unclear whether MHC-linked signals can also affect male reproductive strategies. We used horses ( Equus caballus ) to study this question under experimental conditions. Twelve stallions were individually exposed either to an unfamiliar MHC-similar mare and then to an unfamiliar MHC-dissimilar mare, or vice versa. Each exposure lasted over a period of four weeks. Peripheral blood testosterone levels were determined weekly. Three ejaculates each were collected in the week after exposure to both mares (i.e. in the ninth week) to determine mean sperm number and sperm velocity. We found high testosterone levels when stallions were kept close to MHC-dissimilar mares and significantly lower ones when kept close to MHC-similar mares. Mean sperm number per ejaculate (but not sperm velocity) was positively correlated to mean testosterone levels and also affected by the order of presentation of mares: sperm numbers were higher if MHC-dissimilar mares were presented last than if MHC-similar mares were presented last. We conclude that MHC-linked signals influence testosterone secretion and semen characteristics, two indicators of male reproductive strategies.

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'.

scholarly journals Large brains, short life: selection on brain size impacts intrinsic lifespan

2019 ◽  
Vol 15 (5) ◽  
pp. 20190137 ◽  
Author(s):  
Alexander Kotrschal ◽  
Alberto Corral-Lopez ◽  
Niclas Kolm
Keyword(s):  
Poecilia Reticulata ◽  
Brain Size ◽  
Positive Association ◽  
Energetic Cost ◽  
Accelerated Ageing ◽  
Extrinsic Mortality ◽  
Somatic Maintenance ◽  
Cognitive Benefits ◽  
In The Wild ◽  
Positive Correlations

The relationship between brain size and ageing is a paradox. The cognitive benefits of large brains should protect from extrinsic mortality and thus indirectly select for slower ageing. However, the substantial energetic cost of neural tissue may also impact the energetic budget of large-brained organisms, causing less investment in somatic maintenance and thereby faster ageing. While the positive association between brain size and survival in the wild is well established, no studies exist on the direct effects of brain size on ageing. Here we test how brain size influences intrinsic ageing in guppy ( Poecilia reticulata ) brain size selection lines with 12% difference in relative brain size. Measuring survival under benign conditions, we find that large-brained animals live 22% shorter than small-brained animals and the effect is similar in both males and females. Our results suggest a trade-off between investment into brain size and somatic maintenance. This implies that the link between brain size and ageing is contingent on the mechanism of mortality, and selection for positive correlations between brain size and ageing should occur mainly under cognition-driven survival benefits from increased brain size. We show that accelerated ageing can be a cost of evolving a larger brain.

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