Data from: Social structure of the harem-forming promiscuous fruit bat, Cynopterus sphinx, is the harem truly important?

Bats are social animals and display a diverse variety of mating and social systems, with most species exhibiting some form of polygyny. Their social organization is fluid and individuals frequently switch partners and roosting sites. While harem-like social organization is observed in multiple tropical species, its importance is contested in many of them. In this study, we investigated the role of harems in the social organization of the old world fruit bat Cynopterus sphinx. Based on regular behavioural observations over a period of 20 months and genetic data from microsatellite markers, we observed that the social organization is flexible, individuals regularly shift between roosts and the social organization resembles a fission–fusion society. Behavioural and genetic analyses suggest that the harems are not strict units of social structure, and the colony does not show signatures of subdivision with harems as behavioural units. We also observed that there was no correlation between individuals with high association index and pairwise relatedness. Our findings indicate that similar to the mating system, the social organization of C. sphinx can also be categorized as a fission–fusion society, and hence the term ‘harem’ is a misnomer. We conclude that the social system of C. sphinx is flexible, with multi-male multi-female organization, and individuals tend to be loyal to a given area rather than a roost.

蝙蝠为群居动物，展现出多样的交配与社会系统，多数物种呈现某种形式的一夫多妻制（polygyny）。其社会组织具有流动性，个体常频繁更换配偶与栖息位点。尽管多种热带物种中均观察到类似后宫（harem）的社会组织结构，但该结构在多数此类物种中的重要性仍存在争议。本研究针对旧大陆果蝠犬蝠（Cynopterus sphinx）的社会组织中的后宫结构角色展开了调查。基于为期20个月的常规行为观测与微卫星标记（microsatellite markers）遗传数据，我们发现该物种的社会组织具备灵活性，个体会定期在栖息位点间移动，其社会组织模式类似于裂合-融合社会（fission–fusion society）。行为与遗传分析表明，后宫并非严格的社会结构单元，且该种群未呈现出以后宫为行为单元的群体分化特征。我们还观察到，关联指数较高的个体之间，两两亲缘相关性（pairwise relatedness）并无显著关联。本研究结果显示，与交配系统一致，犬蝠的社会组织同样可归类为裂合-融合社会，因此“后宫”这一术语实为误称。我们最终得出结论：犬蝠的社会系统具有灵活性，属于多雄多雌的组织模式，个体更倾向于忠于特定区域而非某一栖息位点。