Data from: Phenotypic variation and covariation indicate high evolvability of acoustic communication in crickets

Studying the genetic architecture of sexual traits provides insight into the rate and direction at which traits can respond to selection. Traits associated with few loci and limited genetic and phenotypic constraints tend to evolve at high rates typically observed for secondary sexual characters. Here, we examined the genetic architecture of song traits and female song preferences in the field crickets Gryllus rubens and G. texensis. Song and preference data were collected from both species and interspecific F1 and F2 hybrids. We first analysed phenotypic variation to examine interspecific differentiation and trait distributions in parental and hybrid generations. Then, the relative contribution of additive and additive-dominance variation was estimated. Finally, phenotypic variance-covariance (P) matrices were estimated to evaluate the multivariate phenotype available for selection. Song traits and preferences had unimodal trait distributions and hybrid offspring were intermediate with respect to the parents. We uncovered additive and dominance variation in song traits and preferences. For two song traits we found evidence for X-linked inheritance. On one hand, the observed genetic architecture does not suggest rapid divergence, although sex-linkage may have allowed for somewhat higher evolutionary rates. On the other hand, P matrices revealed that multivariate variation in song traits aligned with major dimensions in song preferences, suggesting a strong selection response. We also found strong covariance between the main traits that are sexually selected and traits that are not directly selected by females, providing an explanation for the striking multivariate divergence in male calling songs despite limited divergence in female preferences.探究性征的遗传结构（genetic architecture），能够为理解性状响应选择的速率与方向提供关键视角。受少数基因座调控、遗传与表型限制有限的性状，往往以较高速率演化，这类情况常见于第二性征（secondary sexual characters）。本研究以红足田野蟋蟀（Gryllus rubens）与得州田野蟋蟀（G. texensis）为研究对象，考察其鸣唱性状与雌性鸣唱偏好的遗传结构。研究采集了两个亲本物种以及种间F1、F2杂交后代的鸣唱与偏好数据：首先通过分析表型变异，考察亲本与杂交世代间的种间分化及性状分布；随后估算加性与加性-显性变异的相对贡献；最后构建表型方差-协方差（P）矩阵，评估可供选择作用的多变量表型空间。研究结果显示，鸣唱性状与偏好均呈现单峰性状分布，杂交后代的表型介于两个亲本之间；我们在鸣唱性状与偏好中检测到了加性与显性变异，其中两项鸣唱性状存在X连锁遗传（X-linked inheritance）的证据。一方面，尽管性连锁可能一定程度上提升了演化速率，但本次观测到的遗传结构并未提示存在快速分化；另一方面，P矩阵分析表明，鸣唱性状的多变量变异与雌性鸣唱偏好的主要维度高度契合，提示其具备较强的选择响应能力。此外，我们发现受性选择的核心性状与未被雌性直接选择的性状间存在强烈协方差，这为雄性鸣唱在雌性偏好分化有限的情况下仍出现显著多变量分化提供了合理解释。