Fritzsche Karoline, Booksmythe Isobel, Arnqvist Göran
Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Curr Biol. 2016 Sep 26;26(18):2522-2526. doi: 10.1016/j.cub.2016.07.018. Epub 2016 Sep 1.
The reversal of conventional sex roles was enigmatic to Darwin, who suggested that it may evolve when sex ratios are female biased [1]. Here we present direct evidence confirming Darwin's hypothesis. We investigated mating system evolution in a sex-role-reversed beetle (Megabruchidius dorsalis) using experimental evolution under manipulated sex ratios and food regimes. In female-biased populations, where reproductive competition among females was intensified, females evolved to be more attractive and the sex roles became more reversed. Interestingly, female-specific mating behavior evolved more rapidly than male-specific mating behavior. We show that sexual selection due to reproductive competition can be strong in females and can target much the same traits as in males of species with conventional mating systems. Our study highlights two central points: the role of ecology in directing sexual selection and the role that females play in mating system evolution.
传统性别角色的逆转让达尔文感到困惑，他认为当性别比例偏向雌性时，这种逆转可能会进化[1]。在此，我们提供直接证据证实了达尔文的假设。我们利用在可控性别比例和食物条件下的实验进化，研究了一种性别角色逆转的甲虫（背斑巨豆象）的交配系统进化。在雌性占优的种群中，雌性之间的生殖竞争加剧，雌性进化得更具吸引力，性别角色也变得更加逆转。有趣的是，雌性特有的交配行为比雄性特有的交配行为进化得更快。我们表明，由于生殖竞争导致的性选择在雌性中可能很强，并且可以针对与具有传统交配系统物种的雄性大致相同的性状。我们的研究突出了两个要点：生态在引导性选择中的作用以及雌性在交配系统进化中所起的作用。
