Sexual selection in socially-structured, polyandrous populations: Some insights from the fowl

Abstract Sexual selection is widely recognized as the evolutionary agent driving male exaggeration and strategies of intrasexual competition over reproductive opportunities. Two advances have characterized the development of our understanding of sexual selection in recent years. The first was the realization that sexual selection can extend to post-copulatory episodes whenever females mate with multiple males (polyandry). The second concerns the operation of sexual selection in structured population in light of increasing evidence that populations are often non-randomly assembled. Populations of domestic fowl ( Gallus domesticus ) and red junglefowl ( Gallus gallus ), which are typically socially-structured and polyandrous, have offered a convenient vertebrate model system to study patterns and mechanisms of sexual selection, providing a helpful counterpoint to studies of socially monogamous systems. Here, we review our understanding of the way sexual selection operates in these populations, with emphasis on recent work focusing on the interrelated implications of polyandry and social structure.