The number of competitor species is unlinked to sexual dimorphism.
The number of competitor species is unlinked to sexual dimorphism.
复制标题
竞争物种的数量与性别二态性无关。
DOI：
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发表时间：
2014
影响因子：
4.8
通讯作者：
D. Pincheira‐Donoso
中科院分区：
文献类型：
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作者：
Shai Meiri;Amy E Kadison;M. Novosolov;P. Pafilis;J. Foufopoulos;Y. Itescu;P. Raia;D. Pincheira‐Donoso
两性大小二态性（SSD）可以使同一物种的雄性和雌性专攻不同大小的食物，从而最大限度地减少种内竞争。然而，种间竞争被认为限制了两性二态性，因为群落中较大的竞争者会阻止较大的性别进化成更大的体型，而较小的物种可能会阻止较小的性别变得更小。我们利用世界各地岛屿上蜥蜴和食肉哺乳动物性别大小二态性的数据来检验这一预测。由于岛屿群落缺乏活力，而行会物种匮乏，因此通常认为岛屿上的两性大小二态性增强是常见的。种间竞争的强度随着竞争者丰富度的增加而增加，阻碍了二态性的增强。我们测试了哺乳动物食肉动物和蜥蜴的种内性别大小二态性是否随着岛屿物种丰富度的增加而减少。我们进一步计算了岛屿上物种的平均两性二态性，并测试了物种丰富的岛屿是否居住着相对单一的物种。在食肉动物和蜥蜴的家族和行会中，以及用种内和种间的方法，我们始终未能找到物种贫乏的岛屿上有更多两性二形的个体或物种的观点的支持。我们得出结论，要么种间竞争不影响岛屿蜥蜴和食肉动物的性别大小二型性（即特征位移和物种分选在这些分类群中很少见），要么群落或种群中的物种数量不能很好地代表岛屿群落中种间竞争的强度。
Sexual size dimorphism (SSD) can allow males and females of the same species to specialize on different sized food items and therefore minimize intraspecific competition. Interspecific competition, however, is thought to limit sexual dimorphism, as larger competitors in the community will prevent the larger sex from evolving larger size, and smaller species may prevent the smaller sex from becoming even smaller. We tested this prediction using data on the sexual size dimorphism of lizards, and mammalian carnivores, on islands world-wide. Because insular communities are depauperate, and guilds are species-poor, it is often assumed that enhanced sexual size dimorphism is common on islands. The intensity of interspecific competition, hindering enhanced dimorphism, is thought to increase with competitor richness. We tested whether intraspecific sexual size dimorphism of mammalian carnivores and lizards decreases with increasing island species richness. We further computed the average sexual dimorphism of species on islands and tested whether species-rich islands are inhabited by relatively monomorphic species. Within families and guilds across carnivores and lizards, and with both intraspecific and interspecific approaches, we consistently failed to find support for the notion that species-poor islands harbour more sexually dimorphic individuals or species. We conclude that either interspecific competition does not affect the sexual size dimorphism of insular lizards and carnivores (i.e. character displacement and species sorting are rare in these taxa), or that the number of species in an assemblage or guild is a poor proxy for the intensity of interspecific competition in insular assemblages.