Litmer Allison R, Pelley Morgan K, Beaupre Steven J
The Ohio State University, 1314 Kinnear Road, Columbus, OH 43212, USA.
University of Arkansas, 650 W. Dickson Street, Fayetteville, AR 72701, USA.
J Exp Biol. 2025 Aug 15;228(16). doi: 10.1242/jeb.250737. Epub 2025 Aug 14.
Among ectotherms, temperature and food availability are drivers of individual and population characteristics. Increasing night-time temperatures due to climate change can increase energetic demands, potentially amplified or mitigated by prey consumption. Few studies examine night-time temperatures specifically, and consequences of co-occurring changes in the abiotic and biotic environment. Thus, we examined interactions between warming night-time temperatures and prey availability (as a proxy of foraging time and effectiveness), and how they affect food consumption, digestive passage time, metabolizable energy intake (MEI), assimilated energy, and fecal and urate production in a model organism, prairie lizards (Sceloporus consobrinus). Three temperature treatments (current conditions, +2°C night-time increase and +4°C night-time increase) and three levels of prey availability (low, moderate and high) were used to examine multiple scenarios. Prey and warming interacted in non-linear and unpredictable ways to influence food consumption, passage time and MEI. For example, lizards consumed the most food under 2°C warming yet excreted a high proportion of energy resulting in low MEI in comparison to current temperatures. The combined effects of prey availability and night-time warming will be missed by studies only considering single treatment effects. Moreover, physiological processes can have different thermal sensitivities to night-time temperatures, which can vary in unpredictable ways with combined biotic changes. Complex interactions between thermal sensitivities and multiple concurrent environmental changes may be common among ectotherms, complicating our understanding of responses to a shifting climate.
在变温动物中，温度和食物可获得性是个体及种群特征的驱动因素。气候变化导致夜间温度升高会增加能量需求，而猎物消耗可能会放大或减轻这种影响。很少有研究专门考察夜间温度，以及非生物和生物环境同时发生变化的后果。因此，我们研究了夜间温度升高与猎物可获得性（作为觅食时间和效率的指标）之间的相互作用，以及它们如何影响一种模式生物——草原蜥蜴（Sceloporus consobrinus）的食物消耗、消化通过时间、可代谢能量摄入（MEI）、同化能量以及粪便和尿酸生成。我们采用了三种温度处理（当前条件、夜间温度升高2°C和夜间温度升高4°C）以及三种猎物可获得性水平（低、中、高）来考察多种情况。猎物和温度升高以非线性且不可预测的方式相互作用，从而影响食物消耗、通过时间和MEI。例如，与当前温度相比，蜥蜴在温度升高2°C时消耗的食物最多，但排泄出的能量比例较高，导致MEI较低。仅考虑单一处理效应的研究会忽略猎物可获得性和夜间温度升高的综合影响。此外，生理过程对夜间温度可能具有不同的热敏感性，并且这种敏感性可能会随着生物变化的综合作用而以不可预测的方式变化。热敏感性与多种同时发生的环境变化之间的复杂相互作用在变温动物中可能很常见，这使得我们对气候变化响应的理解变得复杂。
