Data from: Limited plasticity in the phenotypic variance-covariance matrix for male advertisement calls in the black field cricket, Teleogryllus commodus

Phenotypic integration and plasticity are central to our understanding of how complex phenotypic traits evolve. Evolutionary change in complex quantitative traits can be predicted using the multivariate breeders’ equation, but such predictions are only accurate if the matrices involved are stable over evolutionary time. Recent study, however, suggests that these matrices are temporally plastic, spatially variable and themselves evolvable. The data available on phenotypic variance-covariance matrix (P) stability are sparse, and largely focused on morphological traits. Here, we compared P for the structure of the complex sexual advertisement call of six divergent allopatric populations of the Australian black field cricket, Teleogryllus commodus. We measured a subset of calls from wild-caught crickets from each of the populations and then a second subset after rearing crickets under common-garden conditions for three generations. In a second experiment, crickets from each population were reared in the laboratory on high- and low-nutrient diets and their calls recorded. In both experiments, we estimated P for call traits and used multiple methods to compare them statistically (Flury hierarchy, geometric subspace comparisons and random skewers). Despite considerable variation in means and variances of individual call traits, the structure of P was largely conserved among populations, across generations and between our rearing diets. Our finding that P remains largely stable, among populations and between environmental conditions, suggests that selection has preserved the structure of call traits in order that they can function as an integrated unit.

表型整合（phenotypic integration）与表型可塑性（phenotypic plasticity）是解析复杂表型性状演化机制的核心议题。利用多元育种方程（multivariate breeders’ equation）可预测复杂数量性状的演化方向，但此类预测仅在相关矩阵在演化时间尺度上保持稳定时才具备准确性。然而，近期研究表明，这类矩阵兼具时间可塑性与空间变异性，且其本身亦可演化。目前关于表型方差-协方差矩阵（phenotypic variance-covariance matrix，简称P矩阵）稳定性的研究数据较为匮乏，且大多聚焦于形态性状。本研究以澳大利亚黑田蟋蟀（Teleogryllus commodus）6个分化异域种群的复杂性求偶鸣叫结构为研究对象，比较了其P矩阵。我们首先采集了各种群野生捕获蟋蟀的部分鸣叫样本，随后将蟋蟀在同质园（common-garden）条件下饲养三代，再次采集其鸣叫样本。在第二项实验中，我们将各种群的蟋蟀置于实验室环境，分别饲喂高营养与低营养日粮，并记录其鸣叫信号。两项实验中，我们均对鸣叫性状的P矩阵进行了估算，并采用多种统计方法开展比较分析：弗吕里层级（Flury hierarchy）、几何子空间比较（geometric subspace comparisons）以及随机尖峰检验（random skewers）。尽管单个鸣叫性状的均值与方差存在显著变异，但P矩阵的结构在不同种群间、不同世代间以及不同饲喂日粮间基本保持保守。我们的研究发现P矩阵在种群间与环境条件下基本稳定，这表明自然选择保留了鸣叫性状的整合结构，使其能够作为一个协同功能单元发挥作用。