Hierarchical variation in phenotypic flexibility across timescales and associated survival selection shape the dynamics of partial seasonal migration

Population responses to environmental variation ultimately depend on within-individual and among-individual variation in labile phenotypic traits that affect fitness, and resulting episodes of selection. Yet, complex patterns of individual phenotypic variation arising within and between time periods, and associated variation in selection, have not been fully conceptualised or quantified. We highlight how structured patterns of phenotypic variation in dichotomous threshold traits can theoretically arise and experience varying forms of selection, shaping overall phenotypic dynamics. We then fit novel multistate models to ten years of band-resighting data from European shags to quantify phenotypic variation and selection in a key threshold trait underlying spatio-seasonal population dynamics: seasonal migration versus residence. First, we demonstrate substantial among-individual variation alongside substantial between-year individual repeatability in within-year phenotypic variation (‘flex...

种群对环境变化的响应，最终取决于影响适合度（fitness）的易变表型性状（labile phenotypic traits）的个体内变异与个体间变异，以及由此引发的选择事件。然而，时段内与时段间产生的个体表型变异的复杂模式，以及与之关联的选择变异，尚未得到充分的概念化与量化。我们阐释了二分阈值性状（dichotomous threshold traits）的结构化表型变异模式在理论上如何产生，并经受不同形式的选择，进而塑造整体表型动态。随后，我们将新型多状态模型（multistate models）应用于欧洲鸬鹚（European shags）长达十年的环志重见数据（band-resighting data），以量化支撑种群时空季节动态的关键阈值性状中的表型变异与选择：即季节性迁徙与居留策略。首先，我们证明了显著的个体间变异，以及年内表型变异中显著的个体间年际重复率（即‘flex...