Vuarin Pauline, Henry Pierre-Yves
UMR 7179 CNRS-MNHN, Muséum National d'Histoire Naturelle, 1 avenue du petit Château, 91800, Brunoy, France,
J Comp Physiol B. 2014 Aug;184(6):683-97. doi: 10.1007/s00360-014-0833-0. Epub 2014 May 22.
Hibernation and daily torpor (heterothermy) have long been assumed to be adaptive responses to seasonal energy shortage. Laboratory studies have demonstrated that food shortage alone can trigger the use of heterothermy. However, their potential to predict heterothermic responses in the wild is limited, and few field studies demonstrate the dependence of heterothermy on food availability under natural conditions. Thus, the view of heterothermy as an energy saving strategy to compensate for food shortage largely remains an untested hypothesis. In this paper, we review published evidence on the proximate role of food availability in heterothermy regulation by endotherms, and emphasize alternative hypotheses that remain to be tested. Most studies have relied on correlative evidence. Manipulations of food availability, that demonstrate the proximate role of food availability, have been conducted in only five free-ranging heterotherms. Several other metabolic constraints covary with food availability and can confound its effect. Shortage in water availability, the nutritional composition of food, or subsequent conversion of food in fat storage all could be actual proximate drivers of heterothermy regulation, rather than food shortage. Social interactions, competition for food and predation also likely modulate the relative strength of food shortage between individuals. The ecological relevance of the dependence of heterothermy on food availability remains to be assessed in field experiments that account for the confounding effects of covarying environmental and internal factors.
长期以来，冬眠和日常蛰伏（异温性）一直被认为是对季节性能量短缺的适应性反应。实验室研究表明，仅食物短缺就能引发异温性的使用。然而，它们预测野生动物异温反应的潜力有限，很少有野外研究能证明在自然条件下异温性对食物可获得性的依赖性。因此，将异温性视为一种补偿食物短缺的节能策略的观点在很大程度上仍然是一个未经检验的假设。在本文中，我们回顾了已发表的关于食物可获得性在恒温动物异温调节中的直接作用的证据，并强调了有待检验的其他假设。大多数研究依赖于相关性证据。仅在五种自由活动的异温动物中进行了食物可获得性的操纵，以证明其直接作用。其他一些代谢限制因素与食物可获得性共同变化，可能会混淆其影响。水的可获得性短缺、食物的营养成分或食物随后转化为脂肪储存，都可能是异温调节的实际直接驱动因素，而不是食物短缺。社会互动、对食物的竞争和捕食也可能调节个体之间食物短缺的相对强度。异温性对食物可获得性的依赖性的生态相关性仍有待在考虑了环境和内部因素共同变化的混杂影响的野外实验中进行评估。
