Natural and experimental cold exposure in adulthood increase the sensitivity to future stressors in a free‐living songbird
Natural and experimental cold exposure in adulthood increase the sensitivity to future stressors in a free‐living songbird
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成年后自然和实验性的寒冷暴露会增加自由生活的鸣禽对未来压力源的敏感性
DOI：
10.1111/1365-2435.14144
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发表时间：
2022
影响因子：
5.2
通讯作者：
Taff, Conor C.
中科院分区：
文献类型：
--
作者：
Vitousek, Maren N.;Houtz, Jennifer L.;Pipkin, Monique A.;Chang van Oordt, David A.;Hallinger, Kelly K.;Uehling, Jennifer J.;Zimmer, Cedric;Taff, Conor C.
随着全球气候的变化，许多物种受到不断变化的热状态的威胁。尽管全球气温不断上升，但一些人口必须应对更频繁或极端的寒冷。在这些人群中，应对寒冷的能力可能是健康的一个重要决定因素。在圈养动物身上进行的实验表明，极端寒冷或快速的温度下降通常会引起糖皮质激素（应激反应的介质）的增加；然而，尚不清楚自由生活的成年动物是否对生态相关的热挑战表现出类似的反应，它们可能更善于缓冲寒冷的影响。人们对寒冷对未来挑战的敏感性的影响也知之甚少。通过对自由生活的双色stachycineta （stachycineta bicoloro）的巢温度进行有针对性的操作，以及一个长期数据集（2888个样本，8年），我们测试了成人低温暴露与糖皮质激素水平之间的关系。自然和实验冷暴露都改变了糖皮质激素的调节。这主要表现在对未来挑战的敏感性上调（压力诱发的水平）。实验冷暴露也增加了急性应激反应的初始速度和持续时间。对长期数据集的分析发现，在寒冷条件下，糖皮质激素的基线水平较高；然而，这种影响的程度很弱。滑动窗口分析揭示了温度最能预测基线和应激诱导的糖皮质激素的时间线的差异。虽然不可预测性通常被认为是压力源的决定性因素，但我们发现，与热不可预测性(包括近期温度变化的程度和负预测误差（经验温度与长期平均值之间的差异）相比，最近的环境温度更能预测循环皮质酮。总之，这些结果表明，热诱导的对未来挑战敏感性的增加可能会使个体对恶化的条件或随后的不同类型的挑战做出更强烈或更迅速的反应，而不会产生基线糖皮质激素大幅升高所导致的成本。这种预备反应可能是适应性的；然而，对其他挑战的敏感性增加也可能代表了热状态变化的被忽视的成本。在《华尔街日报》博客上阅读免费的《简明语言摘要》。
As the global climate shifts, many species are imperilled by changing thermal regimes. Despite rising global temperatures, some populations must contend with more frequent or extreme cold. In these populations, the ability to cope with cold may be an important determinant of fitness.Experiments in captive animals have shown that extreme cold or rapid temperature declines typically elicit an increase in glucocorticoid hormones (mediators of the stress response); however, it is not known whether free‐living adults, which may be better at buffering the effects of cold, show a similar response to ecologically relevant thermal challenges. The effects of cold on the sensitivity to future challenges are also poorly understood.Using targeted manipulations of nest temperature in free‐living tree swallowsTachycineta bicolorand a long‐term dataset (2,888 samples; 8 years), we tested the relationship between cold exposure and glucocorticoid levels in adults.Both natural and experimental cold exposure altered glucocorticoid regulation. This manifested primarily in terms of an upregulation in the sensitivity to future challenges (stress‐induced levels). Experimental cold exposure also increased the initial speed and duration of the acute stress response. Analyses of the long‐term dataset found that baseline glucocorticoids were higher in cold conditions; however, the magnitude of this effect was weak. A sliding window analysis revealed differences in the timeline over which temperature best predicted baseline and stress‐induced glucocorticoids.Although unpredictability is often regarded as a defining factor of stressors, we found that recent ambient temperatures better predicted circulating corticosterone than measures of thermal unpredictability, including the degree of recent temperature change and negative prediction error (the difference between experienced temperatures and long‐term averages).Together, these results suggest that thermally induced increases in the sensitivity to future challenges may prime individuals to respond more strongly or rapidly to worsening conditions, or to subsequent challenges of a different type, without incurring the costs that can result from substantial elevations in baseline glucocorticoids. This kind of preparatory response could be adaptive; however, an increased sensitivity to other challenges could also represent an overlooked cost of changing thermal regimes.Read the free Plain Language Summary for this article on the Journal blog.