Goodman K R, Kelley J P, Welter S C, Roderick G K, Elias D O
Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA.
J Evol Biol. 2015 Feb;28(2):415-27. doi: 10.1111/jeb.12577. Epub 2015 Jan 30.
Changes in sexual signals have the potential to promote rapid divergence and reproductive isolation among populations of animals. Thus, identifying processes contributing to variation in signals is key to understanding the drivers of speciation. However, it is difficult to identify the processes initiating changes in signals in empirical systems because (1) the demographic history of populations under study is usually unclear, and (2) there is no unified hypothesis-testing framework for evaluating the simultaneous contribution of multiple processes. A unique system for study in the Hawaiian Islands, the planthopper species Nesosydne chambersi, offers a clear demographic context to disentangle these factors. By measuring variation in male vibratory sexual signals across different genetic populations on the island of Hawaii, we found that that multiple signal traits varied significantly between populations. We developed a mixed modelling framework to simultaneously test competing hypotheses about which processes contribute to changes in signal traits: genetic drift, sensory drive or reproductive character displacement. Our findings suggest that signal divergence proceeds along different axes for different signal traits under the influence of both neutral and selective processes. They are the first, to our knowledge, to document the relative importance of multiple processes on divergence in sexual signals.
性信号的变化有可能促进动物种群之间的快速分化和生殖隔离。因此，确定导致信号变异的过程是理解物种形成驱动因素的关键。然而，在实证系统中很难确定引发信号变化的过程，原因如下：（1）所研究种群的人口统计学历史通常不明确；（2）没有统一的假设检验框架来评估多个过程的同时作用。夏威夷群岛一种独特的研究系统——稻虱物种Nesosydne chambersi，为理清这些因素提供了清晰的人口统计学背景。通过测量夏威夷岛上不同遗传种群中雄性振动性信号的变异，我们发现多个信号特征在种群之间存在显著差异。我们开发了一个混合建模框架，以同时检验关于哪些过程导致信号特征变化的相互竞争的假设：遗传漂变、感官驱动或生殖特征取代。我们的研究结果表明，在中性和选择过程的影响下，不同的信号特征沿着不同的轴发生信号分化。据我们所知，它们是首个记录多个过程对性信号分化相对重要性的研究。
