Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain.
Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ciudad Real, Spain.
J Evol Biol. 2024 Aug 27;37(9):1035-1042. doi: 10.1093/jeb/voae088.
Exploring the evolutionary architecture of female sexual traits and their potential evolvability is important to understand their possible role as postmating sexual signals. Egg colouration has been proposed to be one of these postmating sexual signals, honestly advertising female quality in birds, especially in blue-green laying species. In this study, we used an animal model in a Bayesian framework to estimate the evolvability of multiple descriptors of blue-green egg colouration and egg size in a wild long-term monitored population of spotless starlings (Sturnus unicolor). Our results show low to moderate heritability (h2 = 0.31-0.44) for 3 egg colour descriptors (blue-green chroma, chroma, and lightness) and egg size. Using the coefficient of additive genetic variance (CVA) and the evolvability (IA) as proxies of evolutionary potential of all components of this trait, we found low values of CVA for all these variables, suggesting a small evolutionary potential of these phenotypic traits, contrasting to previous results reported in another blue-green egg laying species. Our results indicate a modest raw genetic material of this trait on which sexual selection can act upon and, therefore, a small probability for these traits to respond easily to selection.
探索女性性特征的进化结构及其潜在的可进化性对于理解它们作为交配后性信号的可能作用很重要。卵色被认为是这些交配后性信号之一，诚实的广告女性的质量在鸟类中，尤其是在蓝绿色产卵物种中。在这项研究中，我们使用贝叶斯框架中的动物模型来估计在一个经过长期监测的无斑点椋鸟（Sturnus unicolor）野生种群中，多个蓝绿色卵色和卵大小描述符的可进化性。我们的结果显示，对于 3 个卵色描述符（蓝绿色色度、色度和亮度）和卵大小，遗传力较低（h2 = 0.31-0.44）。使用加性遗传方差系数（CVA）和进化能力（IA）作为该性状所有组成部分进化潜力的代表，我们发现所有这些变量的 CVA 值都较低，这表明这些表型性状的进化潜力较小，与之前在另一种蓝绿色产卵物种中报告的结果形成对比。我们的结果表明，这种性状的原始遗传物质适中，性选择可以在此基础上发挥作用，因此这些性状很可能不容易对选择做出反应。
