Obtaining body condition is an important life history challenge that directly impacts individual fitness and is particularly important for hibernating animals, whose maintenance of adequate body fat and mass is essential for survival. It is well-documented that host-associated microorganisms play a vital role in animal physiology and behavior. Recent work demonstrates that gut microbes are associated with fat accumulation and obesity, particularly the phyla Firmicutes and Bacteroidetes. The focus of most microbiome studies has been on human health or involved lab-reared animals used as a model system. However, these microbes likely are important for individual fitness in wild populations and provide potential mechanistic insights into the adaptability and survival of wildlife. Here we tested whether symbiotic microorganisms within the phyla of Firmicutes and Bacteroidetes were associated with summer mass gain in an exceptionally well-studied wild population of yellow-bellied marmots (Marmota flaviventer) by analyzing 207 fecal samples collected over 5 summer active seasons. Results showed that marmots with higher mass gain rates had a greater relative abundance of Firmicutes. In contrast, a higher relative abundance of Bacteroidetes was associated with lower mass gain rates, but only for marmots living in harsher environments. Similar patterns were found at the family level where Ruminococcaceae, a member of Firmicutes, was associated with higher mass gain rates, and Muribaculaceae, a member of Bacteroidetes, was associated with lower mass gain rates in harsher environments. Although correlative, these results highlight the potential importance of symbiotic gut microbiota to mass gain in the wild—a trait associated with survival and fitness in many taxonomic groups.

中文翻译：

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厚壁菌门和拟杆菌门导致雌性专性冬眠者的质量增加变化

获得身体状况是一项重要的生活史挑战，直接影响个体的健康，对于冬眠动物尤其重要，它们维持足够的体脂肪和质量对于生存至关重要。有充分证据表明，宿主相关微生物在动物生理和行为中发挥着至关重要的作用。最近的研究表明，肠道微生物，特别是厚壁菌门和拟杆菌门，与脂肪堆积和肥胖有关。大多数微生物组研究的重点是人类健康或将实验室饲养的动物用作模型系统。然而，这些微生物可能对野生种群的个体健康很重要，并为野生动物的适应性和生存提供了潜在的机制见解。在这里，我们通过分析 5 个夏季活跃季节收集的 207 个粪便样本，测试了厚壁菌门和拟杆菌门内的共生微生物是否与经过充分研究的野生黄腹土拨鼠 (Marmota flaviventer) 种群的夏季体重增加有关。结果表明，增重率较高的土拨鼠的厚壁菌门相对丰度较高。相比之下，较高的拟杆菌门相对丰度与较低的增重率相关，但仅限于生活在恶劣环境中的土拨鼠。在科水平上也发现了类似的模式，其中厚壁菌门的成员瘤胃球菌科与较高的质量增加率相关，而拟杆菌门的成员穆里杆科在较恶劣的环境中与较低的质量增加率相关。尽管相关，但这些结果强调了共生肠道微生物群对野外质量增加的潜在重要性——这是与许多分类群体的生存和适应性相关的特征。