Munoz-Garcia Agusti, Williams Joseph B
Department of Evolution, Ecology, and Organismal Biology, Aronoff Laboratory, 318 West Twelfth Avenue, Columbus, OH, 43210, USA.
Physiol Biochem Zool. 2005 Nov-Dec;78(6):1039-56. doi: 10.1086/432852. Epub 2005 Sep 22.
Studies of basal metabolic rate (BMR), the minimum metabolic rate of postabsorptive, inactive endotherms while in their rest phase and thermal neutral zone, have contributed significantly to our understanding of animal energetics. Besides body mass, the main determinant of BMR, researchers have invoked diet and phylogenetic history as important factors that influence BMR, although their relative importance has been controversial. For 58 species within the Carnivora, we tested the hypothesis that BMR is correlated with home range size, a proxy for level of activity, and diet, using conventional least squares regression (CLSR) and regression based on phylogenetic independent contrasts (PIC). Results showed that BMR of Carnivora was positively correlated with home range size after controlling for body mass, regardless of the statistical method employed. We also found that diet and mass-adjusted home range size were correlated. When we simultaneously tested the effect of diet and mass-adjusted home range on mass-adjusted BMR, home range size was insignificant because of its colinearity with diet. Then we eliminated home range size from our model, and diet proved to be significant with both CLSR and PIC. We concluded that species that eat meat have larger home ranges and higher BMR than species that eat vegetable matter. To advance our understanding of the potential mechanisms that might explain our results, we propose the "muscle performance hypothesis," which suggests that selection for different muscle fiber types can account for the differences in BMR observed between meat eaters and vegetarian species within the Carnivora.
基础代谢率（BMR）是指处于吸收后、静止状态的恒温动物在休息阶段且处于热中性区时的最低代谢率。对基础代谢率的研究极大地增进了我们对动物能量学的理解。除了作为基础代谢率主要决定因素的体重外，研究人员还认为饮食和系统发育史是影响基础代谢率的重要因素，尽管它们的相对重要性一直存在争议。对于食肉目内的58个物种，我们使用传统最小二乘法回归（CLSR）和基于系统发育独立对比（PIC）的回归方法，检验了基础代谢率与活动范围大小（活动水平的一个指标）和饮食相关的假设。结果表明，在控制体重后，无论采用何种统计方法，食肉目的基础代谢率与活动范围大小呈正相关。我们还发现饮食与经体重调整后的活动范围大小相关。当我们同时检验饮食和经体重调整后的活动范围对经体重调整后的基础代谢率的影响时，由于活动范围大小与饮食存在共线性，其影响不显著。然后我们从模型中剔除了活动范围大小，结果证明饮食在CLSR和PIC两种方法下均具有显著影响。我们得出结论，食肉物种比食草物种具有更大的活动范围和更高的基础代谢率。为了进一步理解可能解释我们研究结果的潜在机制，我们提出了“肌肉性能假说”，该假说认为对不同肌肉纤维类型的选择可以解释食肉目内食肉动物和素食动物之间观察到的基础代谢率差异。
