Polygamy slows down diversification in shorebirds

• Here we introduce a novel hypothesis concerning the role of sexual selection in speciation. As an alternative to sexual selection leading to reproductive isolation, the “dispersal to mate” hypothesis predicts that sexual selection pressure may act to slow speciation since polygamous individuals can access additional mates by increased breeding dispersal. High breeding dispersal should hence increase gene flow and reduce diversification in polygamous species (i.e. species under elevated sexual selection pressure). Here we test this hypothesis to assess how polygamy affects population divergence in shorebirds using genetic differentiation and subspecies richness as proxies for diversification. Across 79 populations of ten plover species (genus: Charadrius), in addition to subspecies data from 136 shorebird species, our results suggest that dispersal associated with polygamy may facilitate gene flow and limit population divergence. Therefore, intense sexual selection, as occurring in polygamous species, may act rather as a brake than an engine of speciation in shorebirds. We encourage future research to further investigate this hypothesis using theoretical, direct tracking and genetic approaches which will inevitably improve our understanding of the relationships between sexual selection, dispersal and diversification.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

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