Bozinovic Francisco, Muñoz José L P, Cruz-Neto Ariovaldo P
Center for Advanced Studies in Ecology and Biodiversity and Departamento de Ecologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago 6513677, Chile.
Physiol Biochem Zool. 2007 Jul-Aug;80(4):452-60. doi: 10.1086/518376. Epub 2007 May 2.
Several competing hypotheses attempt to explain how environmental conditions affect mass-independent basal metabolic rate (BMR) in mammals. One of the most inclusive and yet debatable hypotheses is the one that associates BMR with food habits, including habitat productivity. These effects have been widely investigated at the interspecific level under the assumption that for any given species all traits are fixed. Consequently, the variation among individuals is largely ignored. Intraspecific analysis of physiological traits has the potential to compensate for many of the pitfalls associated with interspecific analyses and, thus, to be a useful approach for evaluating hypotheses regarding metabolic adaptation. In this study, we investigated the effects of food quality, availability, and predictability on the BMR of the leaf-eared mouse Phyllotis darwini. BMR was measured on freshly caught animals from the field, since they experience natural seasonal variations in environmental factors (and, hence, variations in habitat productivity) and diet quality. BMR was significantly correlated with the proportion of dietary plants and seeds. In addition, BMR was significantly correlated with monthly habitat productivity. Path analysis indicated that, in our study, habitat productivity was responsible for the observed changes in BMR, while diet per se had no effect on this variable.
有几种相互竞争的假说试图解释环境条件如何影响哺乳动物与体重无关的基础代谢率（BMR）。其中最具包容性但也存在争议的假说之一是将基础代谢率与饮食习惯联系起来，包括栖息地生产力。在假定任何给定物种的所有特征都是固定的情况下，这些影响已在种间水平上得到广泛研究。因此，个体间的差异在很大程度上被忽略了。对生理特征进行种内分析有可能弥补许多与种间分析相关的缺陷，从而成为评估有关代谢适应性假说的一种有用方法。在本研究中，我们调查了食物质量、可获得性和可预测性对叶耳鼠（Phyllotis darwini）基础代谢率的影响。基础代谢率是在野外刚捕获的动物身上测量的，因为它们经历了环境因素的自然季节性变化（因此，栖息地生产力也会变化）以及饮食质量的变化。基础代谢率与膳食植物和种子的比例显著相关。此外，基础代谢率与每月的栖息地生产力显著相关。路径分析表明，在我们的研究中，栖息地生产力是观察到的基础代谢率变化的原因，而饮食本身对该变量没有影响。
