Is speciation adaptive?
Darwin suggested that the action of natural selection can produce new species, but 150 years after the publication of his famous book, ‘On the Origin of Species’, debate still continues on the mechanisms of speciation. New research finds sexual selection to greatly enlarge the scope for adaptive speciation by triggering a positive feedback between mate choice and ecological diversification that can eventually eliminate gene flow between species. By means of a mathematical model, former Postdoctoral Fellow at the Santa Fe Institute and current Postdoctoral Fellow at the Institute of Ecology and Evolution at the University of Bern in Switzerland, Sander van Doorn and fellow colleagues demonstrate that disruptive ecological selection favors the evolution of sexual preferences for ornaments that signal local adaptation. Such preferences induce assortative mating with respect to ecological characters and enhance the strength of disruptive selection. The model predicts that species can split
