Intrasexual competition and sexual selection in cooperative mammals

  title={Intrasexual competition and sexual selection in cooperative mammals},
  author={Tim H. Clutton‐Brock and Sarah J. Hodge and G{\"o}ran Spong and Andrew F Russell and Neil R. Jordan and Nigel Charles Bennett and Lynda L. Sharpe and Marta B. Manser},
In most animals, the sex that invests least in its offspring competes more intensely for access to the opposite sex and shows greater development of secondary sexual characters than the sex that invests most. However, in some mammals where females are the primary care-givers, females compete more frequently or intensely with each other than males. A possible explanation is that, in these species, the resources necessary for successful female reproduction are heavily concentrated and intrasexual… 

Reproductive skew and selection on female ornamentation in social species

The socially diverse African starlings (Sturnidae) are used to demonstrate that the degree of sexual dimorphism in plumage and body size is reduced in cooperatively breeding species as a result of increased selection on females for traits that increase access to reproductive opportunities, other resources, or higher social status.

Intra-sexual selection in cooperative mammals and birds: why are females not bigger and better armed?

The variance in lifetime reproductive success among females appears to be higher than that among males, yet males grow faster, are much heavier as adults and sport larger skulls and incisors for their body lengths than females, suggesting that intra-sexual selection has nevertheless acted more strongly on the competitive traits of males.

Sexual selection in females

Evidence for intrasexual selection in wild female baboons

Intrasexual competition in females: evidence for sexual selection?

  • K. Rosvall
  • Biology, Psychology
    Behavioral ecology : official journal of the International Society for Behavioral Ecology
  • 2011
Understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes.

Reproductive status and testosterone among females in cooperative mole-rat societies.

Sexual Selection and Female Competition

Sexual selection studies have traditionally focused on reproductive competition as a typical male characteristic, and regarded females as largely passive. However, empirical evidence now shows female

Evolution of Phenotypic Sex Differences in Cooperative Species: is Competition an Opposing Force?

  • R. Dias
  • Biology
    Acta Ornithologica
  • 2019
Results indicate that although extrapair matings and environment attributes are determinant to the evolution of sex differences, males and females of cooperative species seem to be more alike than their non-cooperative counterparts.

Competition, breeding success and ageing rates in female meerkats

It is concluded that the intense intrasexual competition between females in cooperatively breeding groups may carry fitness costs over a longer period than is usually recognised.



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This is the first time that a shift in sex roles has been shown in a vertebrate, and it might be explained by a large decline in male abundance, strongly skewing the sex ratio towards females.

Evolution and Development of Sex Differences in Cooperative Behavior in Meerkats

It is shown that female meerkat helpers contribute more to rearing young than males and that female helpers feed female pups more frequently than males, which support the view that direct, mutualistic benefits are important in the evolution of specialized cooperative behavior.

Reproductive skew among males in a female-dominated mammalian society

The data support a ‘‘limited control’’ model of reproductive skew in this species, in which female choice may play a more important role in limiting control by dominant males than do power struggles among males.

Bateman's Principle in Cooperatively Breeding Vertebrates: The Effects of Non-breeding Alloparents on Variability in Female and Male Reproductive Success1

Analysis of genetic estimates of parentage and reproductive success drawn from the literature indicate that in mammals and, to a lesser extent, in birds, variability in direct fitness is greater among females in species characterized by the presence of non-breeding alloparents.

Potential causes and life-history consequences of sexual size dimorphism in mammals

  • J. Isaac
  • Biology, Environmental Science
  • 2005
Evaluated research on the causes of SSD in mammals finds several promising avenues of research are currently overlooked and long-term studies, which have previously been biased toward ungulates, should be carried out on a variety of taxa.

Sexual Selection, Social Competition, and Speciation

Patterns of variation in socially selected characters demonstrate the wisdom of Darwin's distinction between natural and sexual selection, and the applicability of sexual selection theory to social competition in general.

Rank and reproduction in the female spotted hyaena.

Female reproductive success varies with social rank in many gregarious mammals, including primates, ungulates and carnivores, and fertility among high-ranking females appeared to be less vulnerable to fluctuations in the food supply than was that among low- ranking females.

Sexual Selection

I must confess that I am not convinced of the action of sexual selection in producing the colours of insects, but it cannot be denied that these facts are strikingly corroborative of Mr. Darwin's views.

Monogamy and sex change by aggressive dominance in coral reef fish

Social controlled proteandric hermaphroditism is described in the anemone fish Amphiprion, in which females control production of females by aggressive dominance over males.