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The impact of climatic variation on the opportunity for sexual selection

Twiss, S.D.; Thomas, C.J.; Poland, V.F.; Graves, J.A.; Pomeroy, P.P.


C.J. Thomas

V.F. Poland

J.A. Graves

P.P. Pomeroy


Many studies have demonstrated influences of climatic variation on a variety of ecological processes, however, its impact on the potent evolutionary force of sexual selection has largely been ignored. The intensity of sexual selection is a fundamental parameter in animal populations, which depends upon the degree of polygamy and will probably be influenced by the impact of local climatic variation upon ‘environmental potential for polygamy’. Here, we provide evidence of a direct effect of local climatic variation on the intensity of sexual selection, by showing a clear correlation between local weather conditions and inter-annual changes in the degree of polygamy in a long-term study of colonially breeding grey seals (Halichoerus grypus). Our results show that changes in local weather conditions alter the annual proportion of males contributing to the effective population size (Ne) by up to 61%. Consequently, over the ‘lifetime’ of a cohort, a broader range of individuals will contribute genetically to the next generation if local weather conditions are variable. In the context of predicted future changes in climatic variation, these findings have broad implications for population genetics of socially structured animal systems through the major influence that the degree of polygamy has upon Ne.

Journal Article Type Article
Publication Date Feb 1, 2007
Deposit Date Jul 2, 2008
Journal Biology Letters
Print ISSN 1744-9561
Electronic ISSN 1744-957X
Publisher The Royal Society
Peer Reviewed Peer Reviewed
Volume 3
Issue 1
Pages 12-15
Keywords Climate, Polygyny, Reproductive success, Effective population size, Halichoerus grypus.
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