Data from: Causes and consequences of living in closed societies: lessons from a long-term socio-genetic study on Bechstein's bats

Understanding the ecological, behavioural and genetic factors influencing animal social systems is crucial to investigating the evolution of sociality. Despite the recent advances in population genetic methods and the analysis of social interactions, long-term studies exploring the causes and consequences of social systems in wild mammals are rare. Here, we provide a synthesis of 15 years of data on the Bechstein’s bat (Myotis bechsteinii), a species that raises its young in closed societies of 10-45 females living together for their entire lives and where immigration is virtually absent. We discuss the potential causes and consequences of living in closed societies, based on the available data on Bechstein’s bat and other species with similar social systems. Using a combination of observational and genetic data on the bats together with genetic data on an ecto-parasite, we suggest that closed societies in Bechstein’s bats are likely caused by a combination of benefits from cooperation with familiar colony members and parasite pressure. Consequences of this peculiar social system include increased sensitivity to demographic fluctuations and limits to dispersal during colony foundation, which have broad implications for conservation. We also hope to illustrate by synthesising the results of this long-term study the diversity of tools that can be applied to hypothesise about the factors influencing a species’ social system. We are convinced that with the expansion of the number of social mammals for which comparably detailed socio-genetic long-term data are available, future comparative studies will provide deeper insights into the evolution of closed societies.

探究影响动物社会系统的生态、行为与遗传因素，对于解析社会性的演化机制至关重要。尽管近年来种群遗传学方法与社会互动分析技术取得了诸多进展，但针对野生哺乳动物社会系统的成因与后果开展的长期研究仍较为稀缺。本研究整合了针对贝氏鼠耳蝠（Myotis bechsteinii）长达15年的观测数据。该物种以封闭社会群体的形式抚育幼崽，群体由10至45只终生共同栖息的雌性个体组成，几乎不存在个体迁入现象。基于贝氏鼠耳蝠及其他具有类似社会系统的物种的现有研究数据，我们探讨了这类封闭社会群体生活的潜在成因与后果。结合蝙蝠的观测数据与遗传数据，以及其体外寄生虫（ecto-parasite）的遗传数据，我们提出：贝氏鼠耳蝠的封闭社会群体，可能源于与熟悉集群成员合作带来的收益与寄生虫压力的共同作用。这种特殊社会系统的后果包括：对种群数量波动的敏感性提升，以及集群建立过程中的扩散限制，这些结论对物种保护具有广泛的指导意义。此外，我们希望通过整合这项长期研究的成果，展示可用于探究影响物种社会系统的各类因素、构建相关假说的研究工具的多样性。我们坚信，随着拥有详尽社会遗传学（socio-genetic）长期数据的社会哺乳动物类群不断增加，未来的比较研究将为解析封闭社会群体的演化机制提供更深入的洞见。