Evolutionary optimum for male sexual traits characterized using the multivariate Robertson–Price Identity

Phenotypes tend to remain relatively constant in natural populations, suggesting a limit to trait evolution. Although stationary phenotypes suggest stabilizing selection, directional selection is more commonly reported. However, selection on phenotypes will have no evolutionary consequence if the traits do not genetically covary with fitness, a covariance known as the Robertson–Price Identity. The nature of this genetic covariance determines if phenotypes will evolve directionally or whether they reside at an evolutionary optimum. Here, we show how a set of traits can be shown to be under net stabilizing selection through an application of the multivariate Robertson–Price Identity. We characterize how a suite of male sexual displays genetically covaries with fitness in a population of Drosophila serrata. Despite strong directional sexual selection on these phenotypes directly and significant genetic variance in them, little genetic covariance was detected with overall fitness. Instead, ...表型在自然种群中往往保持相对恒定，这表明性状进化存在上限。尽管稳态表型暗示存在稳定选择（stabilizing selection），但定向选择（directional selection）的相关报道更为常见。然而，若性状与适合度（fitness）不存在遗传协变，则对表型的选择不会产生进化效应，这种协变关系被称为罗伯逊-普莱斯恒等式（Robertson–Price Identity）。该遗传协变的性质决定了表型是会发生定向进化，还是会停留在进化最优值处。本研究通过应用多变量罗伯逊-普莱斯恒等式（multivariate Robertson–Price Identity），论证了如何证明一组性状处于净稳定选择作用之下。我们以锯缘果蝇（Drosophila serrata）种群为研究对象，解析了雄性性展示性状组合与适合度之间的遗传协变关系。尽管这些表型直接受到强烈的定向性选择作用，且自身存在显著的遗传方差，但整体适合度与这些性状间的遗传协变却极难被检测到。与之相反，……