Why Sex? A Pluralist Approach Revisited.

Why sexual reproduction predominates in nature remains a mystery. The mystery stems in part from the fact that many of the plausible hypotheses for sex have restrictive assumptions. Two decades ago these limitations inspired the formulation of a 'pluralist' approach in which standalone hypotheses for sex were considered together. Here we review representative literature to address whether this strategy has deepened our understanding of sex. We found surprisingly few papers adopting such an approach, probably reflecting challenges associated with testing multiple mechanisms. Nevertheless, these studies provided new insights, highlighting in particular the potential importance of interaction between parasites and harmful mutations. We conclude with strategies for moving forward, including broader formulations of pluralism and the application of more qualitative types of testing.