Costs of mating competition limit male lifetime breeding success in polygynous mammals

Although differences in breeding lifespan are an important source of variation in male fitness, the factors affecting the breeding tenure of males have seldom been explored. Here, we use cross-species comparisons to investigate the correlates of breeding lifespan in male mammals. Our results show that male breeding lifespan depends on the extent of polygyny, which reflects the relative intensity of competition for access to females. Males have relatively short breeding tenure in species where individuals have the potential to monopolize mating with multiple females, and longer ones where individuals defend one female at a time. Male breeding tenure is also shorter in species in which females breed frequently than in those where females breed less frequently, suggesting that the costs of guarding females may contribute to limiting tenure length. As a consequence of these relationships, estimates of skew in male breeding success within seasons overestimate skew calculated across the lifetime and, in several polygynous species, variance in lifetime breeding success is not substantially higher in males than in females.The Leverhulme Trust, the Isaac Newton Trust, and the European Research Council provided the funding for this study.This is the original submitted version of the article. It does not incorporate changes arising from peer review or editorial work by the publishers. The final peer-reviewed and published version is available at http://rspb.royalsocietypublishing.org/content/281/1786/20140418.abstract. The accepted manuscript is also available at https://www.repository.cam.ac.uk/handle/1810/245568, embargoed until 14 May 2015