Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA; Cornell Lab of Ornithology, Ithaca, NY, USA.
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA; Cornell Lab of Ornithology, Ithaca, NY, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2023 Jun;280:111419. doi: 10.1016/j.cbpa.2023.111419. Epub 2023 Mar 23.
Capricious environments often present wild animals with challenges that coincide or occur in sequence. Conceptual models of the stress response predict that one threat may prime or dampen the response to another. Although evidence has supported this for glucocorticoid responses, much less is known about the effects of previous challenges on energy mobilization. Food limitation may have a particularly important effect, by altering the ability to mobilize energy when faced with a subsequent challenge. We tested the prediction that challenging weather conditions, which reduce food availability, alter the energetic response to a subsequent acute challenge (capture and restraint). Using a three-year dataset from female tree swallows measured during three substages of breeding, we used a model comparison approach to test if weather (temperature, wind speed, and precipitation) over 3- or 72-hour timescales predicted baseline and post-restraint glucose levels, and if so which environmental factors were the strongest predictors. Contrary to our predictions, weather conditions did not affect baseline glucose; however, birds that had experienced lower temperatures over the preceding 72 h tended to have higher stress-induced glucose when faced with an acute stressor. We also saw some support for an effect of rainfall on stress-induced glucose: around the time that eggs hatched, birds that had experienced more rainfall over the preceding 72 h mounted lower responses. Overall, we find support in a wild animal for the idea that the glucose stress response may be primed by exposure to prior challenges.
多变的环境常常给野生动物带来挑战，这些挑战可能同时发生，也可能相继出现。应激反应的概念模型预测，一种威胁可能会引发或抑制对另一种威胁的反应。尽管这一观点在糖皮质激素反应中得到了证实，但对于先前的挑战对能量动员的影响，人们知之甚少。食物限制可能会产生特别重要的影响，因为它会改变在面临后续挑战时动员能量的能力。我们检验了这样一种预测，即恶劣的天气条件会降低食物的可获得性，从而改变随后的急性挑战（捕捉和束缚）对能量的反应。利用雌性树燕在繁殖三个亚阶段期间三年的数据集，我们使用模型比较方法来检验 3 小时或 72 小时时间范围内的天气（温度、风速和降水）是否预测了基线和束缚后的葡萄糖水平，如果是，哪些环境因素是最强的预测因素。与我们的预测相反，天气条件并不影响基线葡萄糖；然而，在前 72 小时经历较低温度的鸟类在面临急性应激源时，其应激诱导的葡萄糖水平往往更高。我们还发现了一些支持降雨对应激诱导的葡萄糖影响的证据：在卵孵化前后，在前 72 小时经历了更多降雨的鸟类的应激反应较低。总的来说，我们在野生动物中发现了一种支持这样一种观点的证据，即葡萄糖应激反应可能会因先前的挑战而被激发。
