Axes of multivariate sexual signal divergence among incipient species: concordance with selection, genetic variation, and phenotypic plasticity

Sexual signaling traits are often observed to diverge rapidly among populations, thereby playing a potentially key early role in the evolution of reproductive isolation. While often assumed to reflect divergent sexual selection among populations, patterns of sexual trait diversification might sometimes be biased along axes of standing additive genetic variation and covariation among trait components. Additionally, theory predicts that environmentally-induced phenotypic variation might facilitate rapid trait evolution, suggesting that patterns of divergence between populations should mirror phenotypic plasticity within populations. Here we evaluate the concordance between observed axes of multivariate sexual trait divergence and predicted divergence based on (1) interpopulation variation in sexual selection, (2) additive genetic variances, and (3) temperature-related phenotypic plasticity in male courtship song among geographically isolated populations of the Hawaiian swordtail cricket, ...性信号性状（sexual signaling traits）在不同种群间往往快速分化，进而可能在生殖隔离（reproductive isolation）的早期演化进程中发挥关键作用。尽管这类性状的分化通常被认为反映了种群间的歧化性选择（divergent sexual selection），但性性状的多样化模式有时可能会沿现存加性遗传变异（additive genetic variation）与性状组分间协变（covariation）的轴向产生偏倚。此外，理论预测环境诱导的表型可塑性（phenotypic plasticity）可促进性状的快速演化，这提示种群间的分化模式应当与种群内部的表型可塑性特征相一致。本研究以地理隔离的夏威夷剑尾蟋蟀（Hawaiian swordtail cricket）种群为研究对象，评估了其多变量性信号性状分化的观测轴与基于三类指标预测的分化轴之间的一致性：（1）性选择的种群间变异，（2）加性遗传方差，（3）雄性求偶鸣曲（male courtship song）中与温度相关的表型可塑性……