Morris Jeremy S, Carrier David R
Department of Biology, University of Utah, Salt Lake City, UT, 84112.
Evolution. 2016 Apr;70(4):767-80. doi: 10.1111/evo.12904. Epub 2016 Mar 29.
Lifetime reproductive success of males is often dependent upon the ability to physically compete for mates. However, species variation in social structure leads to differences in the relative importance of intraspecific aggression. Here, we present a large comparative dataset on sexual dimorphism in skeletal shape in Carnivora to test the hypotheses that carnivorans exhibit sexual dimorphism in skeletal anatomy that is reflective of greater specialization for physical aggression in males relative to females and that this dimorphism is associated with the intensity of sexual selection. We tested these hypotheses using a set of functional indices predicted to improve aggressive performance. Our results indicate that skeletal shape dimorphism is widespread within our sample. Functional traits thought to enhance aggressive performance are more pronounced in males. Phylogenetic model selection suggests that the evolution of this dimorphism is driven by sexual selection, with the best-fitting model indicating greater dimorphism in polygynous versus nonpolygynous species. Skeletal shape dimorphism is correlated with body size dimorphism, a common indicator of the intensity of male-male competition, but not with mean body size. These results represent the first evidence of sexual dimorphism in the primary locomotor system of a large sample of mammals.
雄性的终生繁殖成功率通常取决于其为争夺配偶而进行身体竞争的能力。然而，社会结构的物种差异导致种内攻击行为的相对重要性存在差异。在此，我们展示了一个关于食肉目骨骼形状两性异形的大型比较数据集，以检验以下假设：食肉动物在骨骼解剖结构上表现出两性异形，这反映出雄性相对于雌性在身体攻击方面具有更高的专业化程度，并且这种两性异形与性选择的强度相关。我们使用一组预计能提高攻击性能的功能指标来检验这些假设。我们的结果表明，在我们的样本中，骨骼形状的两性异形很普遍。被认为能增强攻击性能的功能特征在雄性中更为明显。系统发育模型选择表明，这种两性异形的进化是由性选择驱动的，最佳拟合模型表明，一夫多妻制物种比非一夫多妻制物种的两性异形更为明显。骨骼形状的两性异形与体型两性异形相关，体型两性异形是雄性间竞争强度的一个常见指标，但与平均体型无关。这些结果首次证明了在大量哺乳动物样本的主要运动系统中存在两性异形。
