Social ties drive post-fission group choice in blue monkeys

Permanent group fissions present rare opportunities for individuals in philopatric groups to select their groupmates. Studying post-fission group choice allows insights into how sociality influences animal decision-making and which social ties are important to group-living individuals. Our first analysis investigated which social ties influenced post-fission group choice in adult female blue monkeys by considering the strength and consistency of their ties with their original group’s members, as well as their dominance relations, relatedness to other female group members, and risk of infanticide. We used these dyadic and nodal characteristics in a separable temporal exponential random graph model to model edge persistence across two timesteps, before vs. after fission. Our second analysis used a conditional logit model to investigate the role of the original group’s resident male in a female’s post-fission group choice, assessing the strength of her tie to him and her vulnerability to i..., Observational data were collected from blue monkeys (Cercopithecus mitis stuhlmanni) in the Kakamega Forest, western Kenya surrounding five instances of group fission that occurred between 2008 and 2019. During the study period, trained observers monitored the different groups on a near daily basis, conducting focal animal samples on all adult females (classified as adults from the day they give birth to their first offspring). Focal animal samples were designed to last 30 min, and were retained in the dataset if they were at least 20 min long. On each day, females were chosen as subjects so that focal samples accumulated evenly across individuals and among different periods of the day (morning, midday, afternoon). Instantaneous recording of the focal subject’s behavior occurred at 1-minute intervals and included the identities of any social partners and individuals in proximity (within 1m). Agonistic interactions (with one individual showing submission) were recorded during focal sampl..., , # Social ties drive post-fission group choice in blue monkeys [https://doi.org/10.5061/dryad.xd2547drj](https://doi.org/10.5061/dryad.xd2547drj) Permanent group fissions present rare opportunities for individuals in philopatric groups to select their groupmates, and so by studying post-fission group choice, we can gain insight into how sociality influences decision-making. Our study investigated which social ties and individual attributes influence post-fission group choice in blue monkeys by considering the strength and consistency of female’s ties to social affiliates, her relatedness to female peers, her relative rank, her vulnerability to infanticide, and her tie with the original group’s resident male. We found that females maintained different kinds of relationships during fission (those with social affiliates and the original group’s resident male). Here we present two datasets (and associated R code) used in this analysis, one (Dataset 1) including attributes of dyadic ties an...,# 社会联结驱动青猴的分裂后群体选择 永久性群体分裂（permanent group fission）为恋巢群居（philopatric）群体中的个体提供了罕见的选择群体伙伴的契机。对分裂后群体选择的研究，能够帮助我们揭示社会性（sociality）如何影响动物的决策行为，以及哪些社会联结（social ties）对群居个体至关重要。我们的第一项分析以成年雌性青猴（blue monkeys）为研究对象，通过考量其与原群体成员间联结的强度与稳定性、支配关系、与其他雌性群体成员的亲缘关系，以及杀婴风险（infanticide），探究了哪些社会联结会影响其分裂后的群体选择。我们基于这些二项关系（dyadic）与节点特征（nodal），采用可分离时间指数随机图模型（separable temporal exponential random graph model），构建了群体分裂前后两个时间节点上的联结存续模型。我们的第二项分析则使用条件logit模型（conditional logit model），探究了原群体定居雄性在雌性分裂后群体选择中所发挥的作用，评估了其与该雄性的联结强度，以及其面临的i...相关风险。 本研究的观测数据采集自肯尼亚西部卡卡梅加森林中的斯图尔曼青猴（Cercopithecus mitis stuhlmanni），涵盖了2008年至2019年间发生的5次群体分裂事件。研究期间，经过专业培训的观测人员几乎每日对各群体进行监测，并对所有成年雌性青猴开展焦点动物取样（focal animal sampling）——雌性个体自产下首胎后代之日起被划定为成年个体。焦点取样的预设时长为30分钟，若取样时长不少于20分钟，则该样本可纳入本数据集。每日选取的雌性取样对象需确保，各个体的焦点取样次数在全天不同时段（上午、午间、下午）均匀分布。研究人员以1分钟为间隔对焦点个体的行为进行瞬时记录，记录内容包括其所有社交伙伴以及身处1米范围内的个体的身份信息。在焦点取样过程中，还记录了存在屈服行为的对抗性互动（agonistic interaction）相关信息...。 [https://doi.org/10.5061/dryad.xd2547drj](https://doi.org/10.5061/dryad.xd2547drj) 永久性群体分裂为恋巢群居群体的个体提供了罕见的选择群体伙伴的契机，因此通过研究分裂后的群体选择行为，我们能够深入理解社会性如何影响个体决策。本研究以青猴为对象，通过考量雌性个体与社交伙伴的联结强度与稳定性、与雌性同伴的亲缘关系、相对等级地位、面临的杀婴风险，以及与原群体定居雄性的联结情况，探究了哪些社会联结与个体属性会影响其分裂后的群体选择。研究发现，雌性个体在群体分裂过程中维系着多种类型的社会关系（包括与社交伙伴以及原群体定居雄性的关系）。本文呈现了本分析所用的两套数据集（及配套的R代码），其中数据集1包含二项关系的相关属性an...