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）是我们理解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变化，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。然而近期的研究表明，这类矩阵兼具时间可塑性、空间变异性，且本身可演化。目前关于表型方差-协方差矩阵（phenotypic variance-covariance matrix，简称P矩阵）稳定性的可用数据较为匮乏，且大多聚焦于形态性状。本研究针对澳大利亚黑田蟋蟀（Teleogryllus commodus）6个分化异域种群的复杂求偶鸣唱结构，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唱样本，随后将各该种群蟋蟀置于共同花园实验条件（common-garden conditions）下饲养三代，再次采集第二组鸣唱样本。在第二项实验中，我们将各种群蟋蟀分别在实验室高营养与低营养饲料条件下饲养，并录制其鸣唱。两项实验中，我们均对鸣唱性状的P矩阵进行了估算，并采用弗吕里层级分析（Flury hierarchy）、几何子空间比较法（geometric subspace comparisons）与随机箭检验法（random skewers）等多种统计方法开展比较。尽管单个鸣唱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、世代间以及不同饲养饲料条件下均保持高度保守。我们的研究发现P矩阵在种群间与环境条件下整体保持稳定，这表明自然选择保留了鸣唱性状的整合结构，使其能够作为一个功能整合单元发挥作用。