Data from: Sexual selection and population divergence I: the influence of socially flexible cuticular hydrocarbon expression in male field crickets (Teleogryllus oceanicus)

Debates about how coevolution of sexual traits and preferences might promote evolutionary diversification have permeated speciation research for over a century. Recent work demonstrates that the expression of such traits can be sensitive to variation in the social environment. Here we examined social flexibility in a sexually selected male trait – cuticular hydrocarbon (CHC) profiles – in the field cricket Teleogryllus oceanicus and tested whether population genetic divergence predicts the extent or direction of social flexibility in allopatric populations. We manipulated male crickets’ social environments during rearing and then characterised CHC profiles. CHC signatures varied considerably across populations and also in response to the social environment, but our prediction that increased social flexibility would be selected in more recently founded populations exposed to fluctuating demographic environments was unsupported. Furthermore, models examining the influence of drift and selection failed to support a role of sexual selection in driving population divergence in CHC profiles. Variation in social environments might alter the dynamics of sexual selection, but our results align with theoretical predictions that the role social flexibility plays in modulating evolutionary divergence depends critically on whether responses to variation in the social environment are homogeneous across populations, or whether gene-by-social-environment interactions occur.

关于性征与性偏好的协同进化如何推动演化多样化的争论，一个多世纪以来始终贯穿于物种形成研究领域。近期研究表明，这类性状的表达会随社会环境的变化而发生敏感响应。本研究以大洋洲庭蟋蟀（Teleogryllus oceanicus）为对象，聚焦其经性选择演化得到的雄性性状——表皮碳氢化合物（cuticular hydrocarbon, CHC）谱型——的社会灵活性，并检验种群遗传分化是否能够预测异域种群社会灵活性的程度与方向。我们在雄性蟋蟀饲养阶段对其社会环境进行操控，随后对CHC谱型进行表征分析。结果显示，CHC特征在不同种群间存在显著差异，同时也会响应社会环境的变化；但我们提出的"在经历波动种群统计环境的新近建群种群中，社会灵活性会受到选择青睐"这一预测，并未得到研究结果的支持。此外，针对遗传漂变与选择影响的模型分析，未发现性选择在驱动CHC谱型种群分化中发挥作用的证据。社会环境的变化或许会改变性选择的动态，但本研究结果与理论预测相符：社会灵活性在调控演化分化中所扮演的角色，关键取决于种群对社会环境变化的响应是否具有一致性，抑或是否存在基因-社会环境互作效应。