Data from: A cost of being amicable in a hibernating marmot

Amicable social interactions can enhance fitness in many species, have negligible consequences for some, and reduce fitness in others. For yellow-bellied marmots (Marmota flaviventris), a facultatively social rodent species with demonstrable costs of social relationships during the active season, the effects of sociality on overwinter survival have yet to be fully investigated. Here, we explored how summer social interactions, quantified as social network attributes, influenced marmot survival during hibernation. Using social data collected from 2002 to 2012 on free-living yellow-bellied marmots, we calculated 8 social network measures (in-degree, out-degree, in-closeness, out-closeness, in-strength, out-strength, embeddedness, and clustering coefficient) for both affiliative and agonistic interactions. We performed a principal component analysis (PCA) to reduce those attributes to 3 affiliative (connectedness, strength, and clustering) and 4 agonistic (submissiveness, bullying, strength, and clustering) components. Then, we fitted a generalized linear mixed model to explain variation in overwinter survival as a function of these social components, along with body mass, sex, age, weather conditions, hibernation group size, and hibernation group composition. We found that individuals with stronger amicable relationships were more likely to die during hibernation. This suggests that social relationships, even affiliative ones, need not be beneficial; for yellow-bellied marmots, they can even be fatal.

友好的社会互动可提升诸多物种的适合度，对部分物种影响微乎其微，而对另一些物种则会降低其适合度。针对黄腹旱獭（*Marmota flaviventris*）——一种兼性社会性啮齿类，其活动季的社会关系存在可证实的代价——社会性对其越冬存活的影响仍有待全面探究。本研究探讨了以社会网络属性量化的夏季社会互动如何影响旱獭冬眠期间的存活状况。我们利用2002年至2012年间采集的野生黄腹旱獭社会数据，针对亲和互动与争斗互动分别计算了8项社会网络指标：入度、出度、入亲近中心性、出亲近中心性、入强度、出强度、嵌入度以及聚类系数。随后通过主成分分析（PCA）将上述属性降维，得到3个亲和性主成分（连通性、强度与聚类性）与4个争斗性主成分（顺从性、欺凌行为、强度与聚类性）。我们进一步构建广义线性混合模型，以这些社会主成分为核心自变量，结合体重、性别、年龄、天气状况、冬眠种群规模及冬眠种群组成，解释越冬存活情况的变异。研究发现，拥有更紧密友好社会关系的个体在冬眠期间的死亡风险更高。这表明社会关系——即便为亲和性社会关系——未必均具有益处；对黄腹旱獭而言，此类关系甚至可能是致命的。