The quantification of repeatability has enabled behavioural and evolutionary ecologists to assess the heritable potential of traits. For behavioural traits that vary across life, age‐related variation should be accounted for to prevent biasing the microevolutionary estimate of interest. Moreover, to gain a mechanistic understanding of ontogenetic variation in behaviour, among‐ and within‐individual variance should be quantified across life. We leveraged a 30‐year study of painted turtles (Chrysemys picta) to assess how age contributes to variation in the repeatability of nesting behaviours. We found that four components of nesting behaviour were repeatable and that accounting for age increased the repeatability estimate for maternal choice of canopy cover over nests. We detected canalization (diminished within‐individual variance with age) of canopy cover choice in a reduced data set despite no shift in repeatability. Additionally, random regression analysis revealed that females became more divergent from each other in their choice of canopy cover with age. Thus, properly modelling age‐related variance should more precisely estimate heritable potential, and assessing among‐ and within‐individual variance components in addition to repeatability will offer a more mechanistic understanding of behavioural variation across age.

中文翻译：

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成为习惯的生物：筑巢行为的个体间和个体内差异随年龄变化

可重复性的量化使行为和进化生态学家能够评估性状的遗传潜力。对于随生命变化的行为特征，应考虑与年龄相关的变化，以防止对感兴趣的微观进化估计产生偏差。此外，为了获得对行为个体遗传变异的机制理解，个体之间和个体内部的差异应该在整个生命过程中进行量化。我们利用一项 30 年的锦龟 (Chrysemys picta) 研究来评估年龄如何影响筑巢行为的可重复性变化。我们发现筑巢行为的四个组成部分是可重复的，并且考虑到年龄增加了母体选择冠层而不是巢穴的可重复性估计。尽管重复性没有变化，但我们在减少的数据集中检测到冠层覆盖选择的渠道化（随着年龄的增长而减少个体差异）。此外，随机回归分析显示，随着年龄的增长，雌性在树冠覆盖选择上的差异越来越大。因此，正确建模与年龄相关的方差应该更精确地估计遗传潜力，除了可重复性之外，评估个体间和个体内的方差分量将提供对跨年龄行为变化的更机械的理解。