The lingering impact of stress: brief acute glucocorticoid exposure has sustained, dose-dependent effects on reproduction

Acutely stressful experiences can have profound and persistent effects on phenotype. Across taxa, individuals differ remarkably in their susceptibility to stress. However, the mechanistic causes of enduring stress effects, and of individual differences in stress susceptibility, are poorly understood. Here we tested whether brief, acute increases in glucocorticoid hormones have persistent effects on phenotype, and whether effects differ according to the magnitude or duration of elevation. We used a novel method to non-invasively manipulate hormone levels on short time scales: the application of corticosterone gel to a model egg secured in the nest. Free-living female tree swallows (Tachycineta bicolor) exposed to several brief corticosterone increases during incubation showed dose-dependent differences in behaviour throughout the reproductive period. Birds receiving treatments that simulated higher or longer acute stress responses later provisioned larger broods at lower rates; the resul...急性应激体验可对表型（phenotype）产生深远且持久的影响。在各生物类群中，个体对应激的易感性存在显著差异。然而，学界对于持久应激效应的机制成因，以及个体应激易感性差异的机制，仍缺乏深入认知。本研究旨在验证两点：其一，糖皮质激素（glucocorticoid）的短暂急性升高是否会对表型产生持久影响；其二，其效应是否随激素升高的幅度与持续时长而发生变化。我们采用一种新型方法，可在短时间尺度内无创调控激素水平：将皮质酮（corticosterone）凝胶涂抹于巢内固定的模拟卵上。野外自由栖息的雌性树燕（Tachycineta bicolor）在孵化期间经历数次短暂的皮质酮升高后，其整个繁殖周期内的行为均呈现出剂量依赖性差异。接受模拟更高强度或更长时长急性应激反应处理的个体，后续抚育更大窝雏群时的育雏频率更低；其研究结果……