Department of Ecology and Evolutionary Biology, Federal University of São Paulo (UNIFESP) - Diadema Campus, Rua Prof. Artur Riedel, 275, CEP 09972-270 Diadema, São Paulo, Brazil
School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA.
J Exp Biol. 2021 Mar 22;224(Pt 6):jeb242199. doi: 10.1242/jeb.242199.
Theoretical models predict that lizards adjust their body temperature through behavioral thermoregulation as a function of food availability. However, behavioral thermoregulation is also governed by interactions among physiological and ecological factors other than food availability, such as hydration state, and sometimes it can even conflict with the locomotor activity of animals. Here, we aimed to investigate the role of food intake and hydration state on behavioral thermoregulation and voluntary locomotor activity in the lizard We hypothesized that food intake can influence behavioral thermoregulation via an interaction with hydration state. We also hypothesized that lizards should endeavor to spend as little time as possible to reach their preferred body temperature to defend other physiological and/or ecological functions. We collected lizards in the field and brought them to the laboratory to measure the preferred temperature selected in a thermal gradient and the total distance traveled by them in fed and unfed conditions and with variable hydration state. Our results showed that food consumption was the most important predictor of preferred temperature. In contrast, either the hydration state alone or its interaction with food consumption did not have important effects on the lizards' thermal preference. Also, we found that the total distance traveled by lizards was not affected by food intake and was barely affected by the hydration state. We provide an experimental approach and a robust analysis of the factors that influence behavioral thermoregulation and locomotor activity in a tropical lizard.
理论模型预测，蜥蜴会根据食物的可获得性通过行为体温调节来调节体温。然而，行为体温调节也受到除食物可获得性以外的生理和生态因素的相互作用的控制，例如水合状态，有时甚至会与动物的运动活动发生冲突。在这里，我们旨在研究食物摄入和水合状态对蜥蜴的行为体温调节和自愿运动活动的作用。我们假设食物摄入可以通过与水合状态的相互作用来影响行为体温调节。我们还假设蜥蜴应该努力花费尽可能少的时间来达到其偏好的体温，以保护其他生理和/或生态功能。我们在野外收集蜥蜴并将它们带到实验室，以测量在热梯度中选择的偏好温度以及在喂食和未喂食条件下以及在不同水合状态下蜥蜴所走过的总距离。我们的结果表明，食物消耗是偏好温度的最重要预测因子。相比之下，水合状态本身或其与食物消耗的相互作用对蜥蜴的热偏好没有重要影响。此外，我们发现蜥蜴所走过的总距离不受食物摄入的影响，几乎不受水合状态的影响。我们提供了一种实验方法和一种强大的分析，用于研究热带蜥蜴的行为体温调节和运动活动的影响因素。
