Trading heat and hops for water: dehydration effects on locomotor performance, thermal limits, and thermoregulatory behavior of a terrestrial toad

Due to their highly permeable skin and ectothermy, terrestrial amphibians are challenged by compromises between water balance and body temperature regulation. The way in which such compromises are accommodated, under a range of temperatures and dehydration levels, impacts importantly the behavior and ecology of amphibians. Thus, using the terrestrial toad Rhinella schneideri as a model organism, the goals of this study were twofold. First, we determined how the thermal sensitivity of a centrally relevant trait—locomotion—was affected by dehydration. Secondly, we examined the effects of the same levels of dehydration on thermal preference and thermal tolerance. As dehydration becomes more severe, the optimal temperature for locomotor performance was lowered and performance breadth narrower. Similarly, dehydration was accompanied by a decrease in the thermal tolerance range. Such a decrease was caused by both an increase in the critical minimal temperature and a decrease in the thermal ma...陆生两栖动物因皮肤具有高度通透性且为变温动物（ectothermy），需在水分平衡与体温调节之间做出权衡，由此面临双重挑战。在不同温度与脱水程度下，此类权衡的调控方式对两栖动物的行为与生态特征具有重要影响。为此，本研究以陆生蟾蜍施耐德蟾蜍（Rhinella schneideri）为模式生物，设置了两项研究目标：其一，明确脱水对核心功能性状——运动能力——的热敏感性的影响；其二，探究相同脱水梯度对热偏好与热耐受能力的效应。结果显示，随着脱水程度加剧，运动表现的最适温度降低，且表现宽度收窄；同理，脱水会导致热耐受范围缩小，该范围的缩减由临界最低温度升高与热最大耐受温度降低共同引发……