scholarly journals Extreme cost of rivalry in a monandrous species: male–male interactions result in failure to acquire mates and reduced longevity

2014 ◽  
Vol 281 (1786) ◽  
pp. 20140631 ◽  
Author(s):  
Anne Lizé ◽  
Thomas A. R. Price ◽  
Chloe Heys ◽  
Zenobia Lewis ◽  
Gregory D. D. Hurst
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Social Interactions ◽  
Laboratory Culture ◽  
Female Mating ◽  
Heterospecific Male ◽  
Extreme Polyandry ◽  
Female Behaviour ◽  
Mating Biology ◽  
Mated Female

Mating system variation is profound in animals. In insects, female willingness to remate varies from mating with hundreds of males (extreme polyandry) to never remating (monandry). This variation in female behaviour is predicted to affect the pattern of selection on males, with intense pre-copulatory sexual selection under monandry compared to a mix of pre- and post-copulatory forces affecting fitness under polyandry. We tested the hypothesis that differences in female mating biology would be reflected in different costs of pre-copulatory competition between males. We observed that exposure to rival males early in life was highly costly for males of a monandrous species, but had lower costs in the polyandrous species. Males from the monandrous species housed with competitors showed reduced ability to obtain a mate and decreased longevity. These effects were specific to exposure to rivals compared with other types of social interactions (heterospecific male and mated female) and were either absent or weaker in males of the polyandrous species. We conclude that males in monandrous species suffer severe physiological costs from interactions with rivals and note the significance of male–male interactions as a source of stress in laboratory culture.

Biased sex ratios and parasite mating probabilities

Parasitology ◽  
1993 ◽  
Vol 107 (3) ◽  
pp. 287-295 ◽  
Author(s):  
R. M. May ◽  
M. E. J. Woolhouse
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Mating System ◽  
Sex Ratios ◽  
Theoretical Framework ◽  
Main Body ◽  
Female Mating ◽  
The Mean ◽  
Mated Female

SummaryAn earlier paper (May, 1977) developed a theoretical framework for exploring the consequences of dioecy for the population dynamics of schistosomes, assuming an unbiased sex ratio. This paper extends the analysis to biased sex ratios, as have been reported in practice. We consider the relationships of the mean number and distribution of worms among hosts, the sex ratio, and the mating system (monogamous or polygamous) to: (i) the female mating probability, Φ the prevalence of mated female worms. Ω: and (iii) the mean number of mated female worms per host, ξ. Among other results, we show how high values of Φ are associated with male-biased sex ratios and polygamous mating; that Ω is independent of the mating system and is relatively unaffected by the sex ratio; and that ξ is maximal for unbiased sex ratios given monogamous mating, and for female-biased sex ratios if mating is polygamous. These results, together with the confounding effects of the mean number and distribution of worms, are described in detail in the main body of the paper.

scholarly journals Mate Choice, Sex Roles and Sexual Cognition in Vertebrates: Mate Choice Turns Cognition or Cognition Turns Mate Choice?

2021 ◽  
Vol 9 ◽  
Author(s):  
Theodora Fuss
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Mating System ◽  
Cognitive Abilities ◽  
Cognitive Skills ◽  
Sex Roles ◽  
Environmental Changes ◽  
Antipredator Behavior ◽  
Energy Levels ◽  
Problem Solver

The idea of “smart is sexy,” meaning superior cognition provides competitive benefits in mate choice and, therefore, evolutionary advantages in terms of reproductive fitness, is both exciting and captivating. Cognitively flexible individuals perceive and adapt more dynamically to (unpredictable) environmental changes. The sex roles that females and males adopt within their populations can vary greatly in response to the prevalent mating system. Based on how cognition determines these grossly divergent sex roles, different selection pressures could possibly shape the (progressive) evolution of cognitive abilities, suggesting the potential to induce sexual dimorphisms in superior cognitive abilities. Associations between an individual’s mating success, sexual traits and its cognitive abilities have been found consistently across vertebrate species and taxa, providing evidence that sexual selection may well shape the supporting cognitive prerequisites. Yet, while superior cognitive abilities provide benefits such as higher feeding success, improved antipredator behavior, or more favorable mate choice, they also claim costs such as higher energy levels and metabolic rates, which in turn may reduce fecundity, growth, or immune response. There is compelling evidence in a variety of vertebrate taxa that females appear to prefer skilled problem-solver males, i.e., they prefer those that appear to have better cognitive abilities. Consequently, cognition is also likely to have substantial effects on sexual selection processes. How the choosing sex assesses the cognitive abilities of potential mates has not been explored conclusively yet. Do cognitive skills guide an individual’s mate choice and does learning change an individual’s mate choice decisions? How and to which extent do individuals use their own cognitive skills to assess those of their conspecifics when choosing a mate? How does an individual’s role within a mating system influence the choice of the choosing sex in this context? Drawing on several examples from the vertebrate world, this review aims to elucidate various aspects associated with cognitive sex differences, the different roles of males and females in social and sexual interactions, and the potential influence of cognition on mate choice decisions. Finally, future perspectives aim to identify ways to answer the central question of how the triad of sex, cognition, and mate choice interacts.

scholarly journals Sexually selected females in the monogamous Western Australian seahorse

2006 ◽  
Vol 274 (1609) ◽  
pp. 521-525 ◽  
Author(s):  
Charlotta Kvarnemo ◽  
Glenn I Moore ◽  
Adam G Jones
Keyword(s):  
Sexual Selection ◽  
Sex Ratio ◽  
Mating System ◽  
Genetic Study ◽  
Mating Success ◽  
Male Preference ◽  
Monogamous Species ◽  
Adult Sex Ratio ◽  
Western Australian ◽  
Selection Differentials

Studies of sexual selection in monogamous species have hitherto focused on sexual selection among males. Here, we provide empirical documentation that sexual selection can also act strongly on females in a natural population with a monogamous mating system. In our field-based genetic study of the monogamous Western Australian seahorse, Hippocampus subelongatus , sexual selection differentials and gradients show that females are under stronger sexual selection than males: mated females are larger than unmated ones, whereas mated and unmated males do not differ in size. In addition, the opportunity for sexual selection (variance in mating success divided by its mean squared) for females is almost three times that for males. These results, which seem to be generated by a combination of a male preference for larger females and a female-biased adult sex ratio, indicate that substantial sexual selection on females is a potentially important but under-appreciated evolutionary phenomenon in monogamous species.

2. Mating systems, or who goes with whom, and for how long

2018 ◽  
pp. 16-33
Author(s):  
Leigh W. Simmons
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Social Relationships ◽  
Breeding Season ◽  
Mating Systems ◽  
Practical Applications ◽  
Multiple Partners ◽  
Monogamous Species ◽  
Genetic Techniques ◽  
Males And Females

‘Mating systems, or who goes with whom, and for how long’ examines the variation in how males and females associate during the breeding season, ranging from brief couplings with multiple partners to lifelong monogamy. It also shows how the discovery that females mate with many partners, even in supposedly monogamous species such as songbirds, was made possible by modern genetic techniques. Variation in mating systems holds considerable implications for the operation of sexual selection. The way that animal mating systems have been explained historically is outlined before considering how a more contemporary understanding of genetic and social relationships has reshaped our thinking and how understanding a species’ mating system can have practical applications.

Sexual dimorphism of the major chela and sex ratio as indicators of the mating system in the estuarine snapping shrimp Alpheus colombiensis Wicksten, 1988 (Decapoda: Caridea: Alpheidae)

2020 ◽  
Vol 40 (6) ◽  
pp. 649-656
Author(s):  
Juan C Azofeifa-Solano ◽  
Jeffrey A Sibaja-Cordero ◽  
Ingo S Wehrtmann
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Mating System ◽  
Mate Guarding ◽  
Female Size ◽  
Monogamous Species ◽  
Low Degree ◽  
Adult Sex Ratio ◽  
Snapping Shrimps

Abstract The sexual selection over traits that favor access to mating partners could promote the emergence of sexual dimorphism when the pressure is different between sexes. Monogamous species are considered to have a low degree of sexual dimorphism. The highly diverse snapping shrimps are usually regarded as monogamous, but the mating system has been studied only in few species. We aimed to provide insights into the mating system and sexual dimorphism of Alpheus colombiensisWicksten, 1988. The adult sex ratio was female biased, and solitary ovigerous females were found, suggesting a temporary mate guarding type of mating system. Our results also revealed sexual dimorphism on the snapping claw, which is larger in males than in females. The male’s snapping claw is probably under sexual selection, which can be mediated by male-male competition or female choice. We also estimated the A. colombiensis female size at maturity at 5.2 ± 0.76 mm. Our results contradict the common idea that snapping shrimps are monogamous species, and support that A. colombiensis probably have a temporary mate guarding (e.g., males can sexually interact with more than one female, in opposition to sexual monogamy). This study also sustains the growing evidence that alpheid shrimps display snapping claw sexual dimorphism.

scholarly journals Female behaviour plays a critical role in controlling murine pregnancy block

2009 ◽  
Vol 276 (1662) ◽  
pp. 1723-1729 ◽  
Author(s):  
Stuart D Becker ◽  
Jane L Hurst
Keyword(s):  
Critical Period ◽  
Critical Role ◽  
Reproductive Investment ◽  
Dominant Male ◽  
Critical Periods ◽  
Nest Sites ◽  
Bruce Effect ◽  
Male Scent ◽  
Female Behaviour ◽  
Mated Female

Exposure of recently mated female rodents to unfamiliar male scents during daily prolactin surges results in pregnancy failure (the ‘Bruce effect’). Control of nasal contact with male scents during these narrow windows of sensitivity could allow females to maintain or terminate pregnancy, but female behavioural changes specifically during this critical period have not been investigated. We examined the approach or avoidance of familiar stud strain and unfamiliar male scents by recently mated female mice. Females that maintained pregnancy avoided both unfamiliar and familiar male scent during critical periods of susceptibility for the Bruce effect. By contrast, females that did not maintain pregnancy showed a sharp rise in the time spent with unfamiliar male scent during this critical period. Manipulation of the social status of unfamiliar and stud strain scent donors did not affect the likelihood of pregnancy block, although females spent more time with dominant male scents across all time periods. The ability to control the Bruce effect through behaviour during brief sensitivity just before dusk, when females are likely to be in nest sites, provides a mechanism by which females may adjust their reproductive investment according to nest site social stability and likelihood of offspring survival.

scholarly journals Sexual selection is a form of social selection

2012 ◽  
Vol 367 (1600) ◽  
pp. 2266-2273 ◽  
Author(s):  
Bruce E. Lyon ◽  
Robert Montgomerie
Keyword(s):  
Sexual Selection ◽  
Social Interactions ◽  
Social Selection ◽  
Reproductive Competition ◽  
Selection Theory ◽  
Males And Females ◽  
Female Roles ◽  
Comprehensive Framework ◽  
Natural And Sexual Selection ◽  
Lines Of Evidence

Social selection influences the evolution of weapons, ornaments and behaviour in both males and females. Thus, social interactions in both sexual and non-sexual contexts can have a powerful influence on the evolution of traits that would otherwise appear to be detrimental to survival. Although clearly outlined by West-Eberhard in the early 1980s, the idea that social selection is a comprehensive framework for the study of ornaments and weapons has largely been ignored. In West-Eberhard's view, sexual selection is a form of social selection—a concept supported by several lines of evidence. Darwin's distinction between natural and sexual selection has been useful, but recent confusion about the limits of sexual selection suggests that some traits are not easily categorized as naturally or sexually selected. Because social selection theory has much to offer the current debates about both sexual selection and reproductive competition in females, it is sometimes viewed, narrowly, to be most useful when considering female roles. However, social selection theory encompasses much more than female reproductive competition. Our goal here was to provide that broader perspective.

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