Social competition and selection in males and females

Abstract

During the latter half of the last century, evidence of reproductive competition between males and male selection by females led to the development of a stereotypical view of sex differences that characterized males as competitive and aggressive, and females as passive and choosy, which is currently being revised. Here, we compare social competition and its consequences for selection in males and females and argue that similar selection processes operate in both sexes and that contrasts between the sexes are quantitative rather than qualitative. We suggest that classifications of selection based on distinction between the form of competition or the components of fitness that are involved introduce unnecessary complexities and that the most useful approach in understanding the evolution and distribution of differences and similarities between the sexes is to compare the operation of selection in males and females in different reproductive systems.

Responses to social and environmental stress are attenuated by strong male bonds in wild macaques

“…Our results contribute to these findings by showing that wild, nonphilopatric males also benefit from maintaining strong bonds to their top partners via attenuated responses to noncatastrophic daily stressful situations. Therefore, our study suggests that the ways in which social mammals affiliate, cooperate, and compete among each other is not fundamentally different in gregarious males and females (35,39,66,82,83). Thus, the attenuation of the stress response triggered by diverse sources is yet another adaptive benefit accruing from the establishment and maintenance of strong social bonds in either sex.…”

The sexual selection paradigm: have we overlooked other mechanisms in the evolution of male ornaments?

“…The stickleback is unusual in that the male alone cares for the offspring, but male care and the provisioning of resources critical for offspring survival are common in a range of species, across taxa [35]. Moreover, social selection is acknowledged to operate in both sexes during reproduction [4, 5,12], although its role in the evolution of ornaments has mainly been investigated in females, whereas male ornaments are still typically assumed to arise through classic Darwinian sexual selection. We end by urging researchers to pay more attention to alternative explanations than sexual selection when investigating the evolution and maintenance of male ornaments.…”

“…Second, ornaments could be adopted as indicators of mate quality in mate choice, or of competitive ability in the competition for females, and be favoured by sexual selection for improved mating and fertilization success [10,11]. Yet teasing apart the relative importance of sexual and social selection in driving the evolution of the ornaments can be difficult [12]. This has resulted in all selection related to reproduction sometimes being referred to as sexual selection.…”

Female competition and aggression: interdisciplinary perspectives

“…As highlighted in this Theme Issue by Clutton-Brock & Huchard [80], there are many qualitative similarities in intrasexual competition between males and females, as exemplified by instances of competition for resources needed for survival and reproduction among social or group-living species (see also [3,4,79]). For both sexes, living in groups intensifies competition for limited resources, such that selection favours traits that enhance competitive ability.…”

“…Similar competitive traits, including displays and ornaments, as well as weaponry and aggression, are found in both sexes to varying degrees, and competition for resources is mediated by social mechanisms that operate both within and between groups. Moreover, the selection pressures responsible for the evolution of competitive traits in females often appear similar to those in males, including intrasexual competition for breeding opportunities and to attract preferred mates [5][6][7]36,79,80].…”