Preston, B. T. and Stevenson, I. R. and Pemberton, J. M. and Coltman, D. W. and Wilson, Kenneth (2003) Overt and covert competition in a promiscuous mammal : the importance of weaponry and testes size to male reproductive success. Proceedings of the Royal Society B : Biological Sciences, 270 (1515). pp. 633-640.Full text not available from this repository.
Male contests for access to receptive females are thought to have selected for the larger male body size and conspicuous weaponry frequently observed in mammalian species. However, when females copulate with multiple males within an oestrus, male reproductive success is a function of both pre- and post-copulatory strategies. The relative importance of these overt and covert forms of sexual competition has rarely been assessed in wild populations. The Soay sheep mating system is characterized by male contests for mating opportunities and high female promiscuity. We find that greater horn length, body size and good condition each independently influence a male's ability to monopolize receptive females. For males with large horns at least, this behavioural success translates into greater siring success. Consistent with sperm-competition theory, we also find that larger testes are independently associated with both higher copulation rates and increased siring success. This advantage of larger testes emerges, and strengthens, as the number of oestrous females increases, as dominant males can no longer control access to them all. Our results thus provide direct quantitative evidence that male reproductive success in wild populations of mammals is dependent upon the relative magnitude of both overt contest competition and covert sperm competition.
|Journal or Publication Title:||Proceedings of the Royal Society B : Biological Sciences|
|Uncontrolled Keywords:||Horn ; Copulation Frequency ; Operational Sex Ratio ; Sperm Competition ; Raffle Mechanism ; Sexual Selection|
|Subjects:||Q Science > QH Natural history > QH301 Biology|
|Departments:||Faculty of Science and Technology > Lancaster Environment Centre|
|Deposited By:||Dr Kenneth Wilson|
|Deposited On:||20 May 2008 16:01|
|Last Modified:||26 Jul 2012 18:29|
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