Environmental drivers of varying selective optima in a small passerine: a multivariate, multiepisodic approach

In changing environments, phenotypic traits are shaped by numerous agents of selection. The optimal phenotypic value maximizing the fitness of an individual thus varies through time and space with various environmental covariates. Selection may differ between different life cycle stages and act on correlated traits inducing changes in the distribution of several traits simultaneously. Despite increasing interests in environmental sensitivity of phenotypic selection, estimating varying selective optima on various traits throughout the life cycle, while considering (a)biotic factors as potential selective agents has remained challenging. Here, we provide a statistical model to measure varying selective optima from longitudinal data. We apply our approach to analyse environmental sensitivity of phenotypic selection on egg-laying date and clutch size throughout the life cycle of a white-throated dipper population. We show the presence of a joint optimal phenotype that varies over the 35-yr ...在变化的环境中，表型性状（phenotypic traits）受众多选择因子（agents of selection）塑造。使个体适合度（fitness）最大化的最优表型值，会随各类环境协变量在时间与空间中发生动态变化。选择作用在不同生活史阶段（life cycle stages）可能存在差异，且可作用于相关性状（correlated traits），同时引发多个性状的分布发生改变。尽管学界对表型选择的环境敏感性的研究关注度与日俱增，但在将非生物（abiotic）与生物（biotic）因子作为潜在选择因子纳入考量的前提下，估算整个生活史中各性状的动态选择最优值仍颇具挑战。本研究提出一种可从纵向数据（longitudinal data）中估算动态选择最优值的统计模型。我们将该方法应用于分析白喉河乌（white-throated dipper）种群整个生活史中，产卵日期（egg-laying date）与窝卵数（clutch size）的表型选择环境敏感性。研究证实存在随35年……动态变化的联合最优表型……