Miles Meredith C, Cheng Samantha, Fuxjager Matthew J
Department of Biology, Wake Forest University, Winston-Salem, North Carolina, 27109.
National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, California, 93106.
Evolution. 2017 May;71(5):1406-1416. doi: 10.1111/evo.13213. Epub 2017 Mar 21.
Gestural displays are incorporated into the signaling repertoire of numerous animal species. These displays range from complex signals that involve impressive and challenging maneuvers, to simpler displays or no gesture at all. The factors that drive this evolution remain largely unclear, and we therefore investigate this issue in New World blackbirds by testing how factors related to a species' geographical distribution and social mating system predict macro-evolutionary patterns of display elaboration. We report that species inhabiting temperate regions produce more complex displays than species living in tropical regions, and we attribute this to (i) ecological factors that increase the competitiveness of the social environment in temperate regions, and (ii) different evolutionary and geological contexts under which species in temperate and tropical regions evolved. Meanwhile, we find no evidence that social mating system predicts species differences in display complexity, which is consistent with the idea that gestural displays evolve independently of social mating system. Together, these results offer some of the first insight into the role played by geographic factors and evolutionary context in the evolution of the remarkable physical displays of birds and other vertebrates.
手势展示被纳入众多动物物种的信号库中。这些展示范围从涉及令人印象深刻且具有挑战性动作的复杂信号，到更简单的展示或根本没有手势。推动这种进化的因素在很大程度上仍不清楚，因此我们通过测试与物种地理分布和社会交配系统相关的因素如何预测展示精细化的宏观进化模式，在新大陆黑鹂中研究这个问题。我们报告说，栖息在温带地区的物种比生活在热带地区的物种产生更复杂的展示，我们将此归因于：（i）增加温带地区社会环境竞争力的生态因素，以及（ii）温带和热带地区物种进化所处的不同进化和地质背景。同时，我们没有发现证据表明社会交配系统能预测展示复杂性的物种差异，这与手势展示独立于社会交配系统进化的观点一致。总之，这些结果首次为地理因素和进化背景在鸟类和其他脊椎动物显著身体展示进化中所起的作用提供了一些见解。
