Arbon Josh J, Morris-Drake Amy, Kern Julie M, Howell Gabrielle M K, Wentzel Jeanette, Radford Andrew N, Nichols Hazel J
School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK.
School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia.
R Soc Open Sci. 2024 Oct 2;11(10):241125. doi: 10.1098/rsos.241125. eCollection 2024 Oct.
Cooperatively breeding societies show distinct interspecific variations in social and genetic organization. Long-term studies provide invaluable data to further our understanding of the evolution and maintenance of cooperative breeding but have also demonstrated how variation exists within species. Here we integrate life-history, behavioural and genetic data from a long-term study of dwarf mongooses in South Africa to document mating, breeding, dispersal and relatedness patterns in this population and compare them to those found in a Tanzanian population at the other extreme of the species' range. Our genetic data reveal high levels of reproductive skew, above that expected through observational data. Dispersal was male-biased and was seen more frequently towards the onset of the breeding season, but females also regularly switched between groups. These patterns of breeding and dispersal resulted in a genetically structured population: individuals were more related to groupmates than outsiders, apart from the unrelated dominant pair, ultimately resulting in reduced inbreeding risk. Our results also demonstrate that dwarf mongooses are largely consistent in their social structure across their sub-Saharan distribution. This work demonstrates the direct and indirect pathways to reproductive success for dwarf mongooses and helps to explain the maintenance of cooperative breeding in the species.
合作繁殖群体在社会和遗传组织方面表现出明显的种间差异。长期研究为增进我们对合作繁殖的进化和维持的理解提供了宝贵数据，但也揭示了物种内部存在的变异情况。在此，我们整合了来自南非对矮獴的长期研究中的生活史、行为和遗传数据，以记录该种群的交配、繁殖、扩散和亲缘关系模式，并将它们与在该物种分布范围另一端的坦桑尼亚种群中发现的模式进行比较。我们的遗传数据揭示了高水平的繁殖偏斜，高于通过观察数据所预期的水平。扩散存在雄性偏向，且在繁殖季节开始时更为频繁，但雌性也会定期在群体间转换。这些繁殖和扩散模式导致了一个具有遗传结构的种群：除了无亲缘关系的优势对之外，个体与群体成员的亲缘关系比与外来者更近，最终降低了近亲繁殖风险。我们的结果还表明，矮獴在撒哈拉以南分布范围内的社会结构在很大程度上是一致的。这项工作展示了矮獴实现繁殖成功的直接和间接途径，并有助于解释该物种合作繁殖的维持机制。
