Data from: Geographic variation in advertisement calls of a Microhylid frog—testing the role of drift and ecology

Acoustic signals for mating are important traits that could drive population differentiation and speciation. Ecology may play a role in acoustic divergence through direct selection (e.g., local adaptation to abiotic environment), constraint of correlated traits (e.g., acoustic traits linked to another trait under selection), and/or interspecific competition (e.g., character displacement). However, genetic drift alone can also drive acoustic divergence. It is not always easy to differentiate the role of ecology versus drift in acoustic divergence. In this study, we tested the role of ecology and drift in shaping geographic variation in the advertisement calls of Microhyla fissipes. We examined three predictions based on ecological processes: (1) the correlation between temperature and call properties across M. fissipes populations; (2) the correlation between call properties and body size across M. fissipes populations; and (3) reproductive character displacement (RCD) in call properties between M. fissipes populations that are sympatric with and allopatric to a congener M. heymonsi. To test genetic drift, we examined correlations among call divergence, geographic distance, and genetic distance across M. fissipes populations. We recorded the advertisement calls from 11 populations of M. fissipes in Taiwan, five of which are sympatrically distributed with M. heymonsi. We found geographic variation in both temporal and spectral properties of the advertisement calls of M. fissipes. However, the call properties were not correlated with local temperature or the callers' body size. Furthermore, we did not detect RCD. By contrast, call divergence, geographic distance, and genetic distance between M. fissipes populations were all positively correlated. The comparisons between phenotypic Qst (Pst) and Fst values did not show significant differences, suggesting a role of drift. We concluded that genetic drift, rather than ecological processes, is the more likely driver for the geographic variation in the advertisement calls of M. fissipes.用于交配的声学信号是推动种群分化与物种形成的关键性状。生态过程可通过多重途径介导声学特征分化：包括针对非生物环境的局部适应所带来的直接选择、受选择关联性状的约束（如与另一受选择性状相关联的声学性状），以及种间竞争（如特征置换）。但仅靠遗传漂变同样可引发声学特征分化，二者在声学分化中的作用往往难以区分。 本研究旨在探究生态过程与遗传漂变对饰纹姬蛙（Microhyla fissipes）广告鸣唱地理变异的塑造作用。我们基于生态过程提出三项验证假设：其一，饰纹姬蛙种群间温度与鸣唱性状的相关性；其二，饰纹姬蛙种群间鸣唱性状与个体体型的相关性；其三，与同属物种孟氏姬蛙（Microhyla heymonsi）同域分布的饰纹姬蛙种群，相较于异域分布种群，其鸣唱性状是否存在生殖特征置换（reproductive character displacement, RCD）。为检验遗传漂变的作用，我们分析了饰纹姬蛙种群间鸣唱分化程度、地理距离与遗传距离三者间的相关性。 我们录制了中国台湾地区11个饰纹姬蛙种群的广告鸣唱，其中5个种群与孟氏姬蛙呈同域分布。研究结果显示，饰纹姬蛙的广告鸣唱在时间特征与频谱特征上均存在地理变异。但鸣唱性状与当地温度及发声个体的体型大小均未表现出相关性。此外，我们未检测到生殖特征置换现象。与之相反，饰纹姬蛙种群间的鸣唱分化程度、地理距离与遗传距离三者均呈显著正相关。表型Qst（Pst）与遗传分化系数（Fst）的比较未发现显著差异，提示遗传漂变发挥了作用。综上，我们认为遗传漂变而非生态过程，更可能是驱动饰纹姬蛙广告鸣唱地理变异的核心因素。