The extent to which the gut microbiota may play a role in latitudinal clines of body mass variation (i.e., Bergmann's rule) remains largely unexplored. Here, we collected wild house mice from three latitudinal transects across North and South America and investigated the relationship between variation in the gut microbiota and host body mass by combining field observations and common garden experiments. First, we found that mice in the Americas follow Bergmann's rule, with increasing body mass at higher latitudes. Second, we found that overall differences in the gut microbiota were associated with variation in body mass controlling for the effects of latitude. Then, we identified specific microbial measurements that show repeated associations with body mass in both wild‐caught and laboratory‐reared mice. Finally, we found that mice from colder environments tend to produce greater amounts of bacteria‐driven energy sources (i.e., short‐chain fatty acids) without an increase in food consumption. Our findings provide motivation for future faecal transplant experiments directly testing the intriguing possibility that the gut microbiota may contribute to Bergmann's rule, a fundamental pattern in ecology.

中文翻译：

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野生家鼠的肠道菌群和伯格曼法则。

肠道菌群可能在体重变化的纬度谱系中发挥作用的程度（即，伯格曼法则）在很大程度上尚待探索。在这里，我们从北美和南美的三个纬度样面收集了野生家鼠，并结合现场观察和常规的花园实验研究了肠道菌群变化与宿主体重之间的关系。首先，我们发现美洲的老鼠遵循伯格曼法则，在高纬度地区体重增加。其次，我们发现肠道菌群的总体差异与控制纬度影响的体重变化有关。然后，我们确定了特定的微生物测量值，这些测量值在野外捕获的和实验室饲养的小鼠中均显示出与体重的重复关联。最后，我们发现，来自较冷环境的小鼠往往会产生大量细菌驱动的能源（即短链脂肪酸），而不会增加食物消耗。我们的发现为未来的粪便移植实验提供了动力，直接测试了肠道菌群可能有助于生态学中一种基本模式-伯格曼法则的有趣可能性。