scholarly journals Postcopulatory sexual selection influences baculum evolution in primates and carnivores

2016 ◽  
Vol 283 (1844) ◽  
pp. 20161736 ◽  
Author(s):  
Matilda Brindle ◽  
Christopher Opie
Keyword(s):  
Sexual Selection ◽  
Reproductive Strategies ◽  
Morphological Variability ◽  
Breeding Systems ◽  
Seasonal Breeding ◽  
Adaptive Function ◽  
Evolutionary Trajectory ◽  
Postcopulatory Sexual Selection ◽  
Phylogenetic Framework ◽  
Postcopulatory Selection

The extreme morphological variability of the baculum across mammals is thought to be the result of sexual selection (particularly, high levels of postcopulatory selection). However, the evolutionary trajectory of the mammalian baculum is little studied and evidence for the adaptive function of the baculum has so far been elusive. Here, we use Markov chain Monte Carlo methods implemented in a Bayesian phylogenetic framework to reconstruct baculum evolution across the mammalian class and investigate the rate of baculum length evolution within the primate order. We then test the effects of testes mass (postcopulatory sexual selection), polygamy, seasonal breeding and intromission duration on the baculum in primates and carnivores. The ancestral mammal did not have a baculum, but both ancestral primates and carnivores did. No relationship was found between testes mass and baculum length in either primates or carnivores. Intromission duration correlated with baculum presence over the course of primate evolution, and prolonged intromission predicts significantly longer bacula in extant primates and carnivores. Both polygamous and seasonal breeding systems predict significantly longer bacula in primates. These results suggest the baculum plays an important role in facilitating reproductive strategies in populations with high levels of postcopulatory sexual selection.

scholarly journals Sex ratio effects on reproductive strategies in humans

2015 ◽  
Vol 2 (1) ◽  
pp. 140402 ◽  
Author(s):  
Ryan Schacht ◽  
Monique Borgerhoff Mulder
Keyword(s):  
Sexual Selection ◽  
Sex Ratio ◽  
Ethnic Group ◽  
Reproductive Strategies ◽  
Situational Factors ◽  
Male Mating ◽  
Mating Effort ◽  
Short Term ◽  
Adult Sex Ratio ◽  
Using Data

Characterizations of coy females and ardent males are rooted in models of sexual selection that are increasingly outdated. Evolutionary feedbacks can strongly influence the sex roles and subsequent patterns of sex differentiated investment in mating effort, with a key component being the adult sex ratio (ASR). Using data from eight Makushi communities of southern Guyana, characterized by varying ASRs contingent on migration, we show that even within a single ethnic group, male mating effort varies in predictable ways with the ASR. At male-biased sex ratios, men's and women's investment in mating effort are indistinguishable; only when men are in the minority are they more inclined towards short-term, low investment relationships than women. Our results support the behavioural ecological tenet that reproductive strategies are predictable and contingent on varying situational factors.

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 The role of oxidative stress in postcopulatory selection

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200065
Author(s):  
Christopher R. Friesen ◽  
Daniel W. A. Noble ◽  
Mats Olsson
Keyword(s):  
Oxidative Stress ◽  
Sexual Selection ◽  
Life History Theory ◽  
Primary Source ◽  
Research Area ◽  
Good Genes ◽  
Atp Production ◽  
Left Behind ◽  
Trade Offs ◽  
Postcopulatory Selection

Two decades ago, von Schantz et al . (von Schantz T, Bensch S, Grahn M, Hasselquist D, Wittzell H. 1999 Good genes, oxidative stress and condition-dependent sexual signals. Proc. R. Soc. B 266, 1–12. ( doi:10.1098/rspb.1999.0597 )) united oxidative stress (OS) biology with sexual selection and life-history theory. This set the scene for analysis of how evolutionary trade-offs may be mediated by the increase in reactive molecules resulting from metabolic processes at reproduction. Despite 30 years of research on OS effects on infertility in humans, one research area that has been left behind in this integration of evolution and OS biology is postcopulatory sexual selection—this integration is long overdue. We review the basic mechanisms in OS biology, why mitochondria are the primary source of ROS and ATP production during oxidative metabolism, and why sperm, and its performance, is uniquely susceptible to OS. We also review how postcopulatory processes select for antioxidation in seminal fluids to counter OS and the implications of the net outcome of these processes on sperm damage, sperm storage, and female and oocyte manipulation of sperm metabolism and repair of DNA to enhance offspring fitness. This article is part of the theme issue ‘Fifty years of sperm competition’.

POSTCOPULATORY SEXUAL SELECTION INCREASES ATP CONTENT IN RODENT SPERMATOZOA

Evolution ◽  
2013 ◽  
Vol 67 (6) ◽  
pp. 1838-1846 ◽  
Author(s):  
Maximiliano Tourmente ◽  
Melissah Rowe ◽  
M. Mar González-Barroso ◽  
Eduardo Rial ◽  
Montserrat Gomendio ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Atp Content ◽  
Postcopulatory Sexual Selection

scholarly journals Maintenance of deceptive gifts in a natural spider population: ecological and demographic factors

2019 ◽  
Vol 30 (4) ◽  
pp. 993-1000
Author(s):  
Maria J Albo ◽  
Valentina Franco-Trecu ◽  
Filip J Wojciechowski ◽  
Søren Toft ◽  
Trine Bilde
Keyword(s):  
Sexual Selection ◽  
Prey Availability ◽  
Operational Sex Ratio ◽  
Life History Strategies ◽  
Power Relationships ◽  
Nuptial Gift ◽  
Short Supply ◽  
Postcopulatory Sexual Selection ◽  
Asymmetric Power ◽  
Pisaura Mirabilis

AbstractAlternative mating tactics are expected to occur predominantly when mate competition is intense, resources are in short supply, or as a result of asymmetric power relationships between individuals. Males of the nuptial gift-giving spider Pisaura mirabilis use a prevailing tactic of offering a nutritive gift (insect prey) and a deceptive tactic of offering a worthless gift (consumed prey) to prospective mates. If the male’s tactic depends on precopulatory male–male competition, worthless gifts should occur primarily late in the season, when the operational sex ratio (OSR) becomes male-biased. If it depends on resource availability and/or postcopulatory sexual selection (sperm competition), worthless gifts should occur mostly early in the mating season, when prey availability is low and most females are unmated (i.e., postcopulatory sexual selection is weak). Nuptial gift construction correlated positively with prey availability and negatively with OSR, suggesting that males increase reproductive effort when resource and mate availability increase. We did not find evidence for body condition affecting male tactic use. Male size had a marked effect on the reproductive tactic employed. Males that matured early in the season were very small and employed mostly the nutritive gift tactic during their short life. Among the males that matured later and persisted through the season, relatively small males employed the worthless gift tactic whereas large males employed the nutritive gift tactic. We suggest that the existence of 2 distinct life-history strategies among males (early small and late large size) interacts with environmental and demographic conditions to maintain the deceptive tactic.

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