Data from: Female sociality and sexual conflict shape offspring survival in a Neotropical primate

Most mammals live in social groups in which members form differentiated social relationships. Individuals may vary in their degree of sociality, and this variation can be associated with differential fitness. In some species, for example, female sociality has a positive effect on infant survival. However, investigations of such cases are still rare, and no previous study has considered how male infanticide might constrain effects of female sociality on infant survival. Infanticide is part of the male reproductive strategy in many mammals, and it has the potential to override, or even reverse, effects of female reproductive strategies, including sociality. Therefore, we investigated the relationships between female sociality, offspring survival, and infanticide risk in wild white-faced capuchin monkeys using long-term data from Santa Rosa, Costa Rica. Female capuchins formed differentiated bonds, and bond strength was predicted by kin relationship, rank difference, and the presence of female infants. Most females formed stable bonds with their top social partners, although bond stability varied considerably. Offspring of highly social females, who were often high-ranking females, exhibited higher survivorship during stable periods compared with offspring of less social females. However, offspring of highly social females were more likely to die or disappear during periods of alpha male replacements, probably because new alpha males are central to the group, and therefore more likely to target the infants of highly social, central females. This study shows that female sociality in mammals can have negative fitness consequences that are imposed by male behavior.多数哺乳动物营社会群体生活，群体成员间会形成具有差异化的社会联结。个体的社会性程度存在差异，而这种差异可能与适合度的分化相关。例如在部分物种中，雌性社会性对幼崽存活率具有正向影响。然而，针对此类案例的研究仍较为匮乏，且此前尚无研究探讨雄性杀婴行为（infanticide）可能会如何制约雌性社会性对幼崽存活率的影响。在多数哺乳动物类群中，杀婴行为属于雄性繁殖策略的一部分，其有可能抵消乃至逆转包括社会性在内的雌性繁殖策略所产生的效应。因此，本研究借助哥斯达黎加圣罗莎（Santa Rosa）的长期监测数据，对野生白面卷尾猴（white-faced capuchin monkeys）的雌性社会性、后代存活率与杀婴风险之间的关联展开了探究。雌性卷尾猴会形成具有差异化的社会联结，联结强度可通过亲缘关系、等级差异以及雌性幼崽的存在情况加以预测。多数雌性个体与其核心社交伙伴之间的联结较为稳定，不过联结的稳定性仍存在显著差异。社会性程度较高的雌性（通常同时为群体高等级个体），其后代在群体稳定时期的存活率要高于社会性程度较低的雌性的后代。但在雄性首领（alpha male）更替阶段，社会性程度较高的雌性的后代死亡或失踪的概率更高，这或许是因为新任雄性首领是群体的核心成员，因而更有可能将社会性较强、处于群体中心的雌性的幼崽作为攻击目标。本研究表明，哺乳动物的雌性社会性可能会因雄性行为而产生不利于适合度的后果。