Dissertation Research: Splitting and Joining Decisions, and Adaptations to Temporal Resource Variation in Long-Haired Spider Monkeys (Ateles Belzebuth Belzebuth)

本项目将调查厄瓜多尔亚苏尼国家公园的长毛蜘蛛猴（Ateles belzebuth belzebuth）的裂变-融合行为及其与生态和社会因素的关系。 蜘蛛猴生活在社会群体中，其中社区的所有成员很少在同一时间出现在同一地点。 相反，社区的子集（子组）暂时关联，并经常改变关联。 很少有研究涉及是什么原因导致个体从这些亚群中分裂或加入这些亚群。 该项目将估计喂养树木的水果量的预期如何影响分组分裂决策，分组融合的竞争或合作性质，以及分组变化在多大程度上受到非食物相关原因（如社会因素）的影响。 为了解释这些问题，本项目将提供证据，证明蜘蛛猴了解在哪里可以找到觅食树，以及何时可以有益地访问这些树。为了实现这些目标，成年雌性将从黎明到黄昏进行为期两周的跟踪，以收集关于亚组变化和资源使用的数据。 此外，还将收集重要饲用树木的结果模式数据，以衡量水果丰富度的细微变化。该项目将澄清我们对亚群形成和分裂的原因的认识，提供对导致裂变-融合社会进化的因素的更清晰的理解，从而为理解灵长类社会系统的进化提供重要的比较信息。 此外，它还将提供灵长类动物拥有心理地图的证据，并将提供灵长类动物对水果可用性随时间变化的理解的第一批数据。

This project will investigate the fission-fusion behavior of long-haired spider monkeys (Ateles belzebuth belzebuth) in the Yasuni National Park, Ecuador, and its relationship to ecological and social factors. Spider monkeys live in social groups in which all of the members of a community are rarely in the same place at the same time. Instead, subsets (subgroups) of the community associate temporarily and change associations frequently. Few studies have addressed what causes individuals to split from or join these subgroups. This project will estimate how the expectation of the amount of fruit in feeding trees affects subgroup splitting decisions, the competitive or cooperative nature of subgroup fusions, and to what extent subgroup changes are influenced by non-food-related causes, such as social factors. To interpret these issues, this project will provide evidence of the level at which spider monkeys understand where to find feeding trees, and when those trees can be profitably visited. To accomplish these goals, adult females will be followed for two-week periods from dawn to dusk to collect data on subgroup changes and resource use. Additionally, data on the fruiting patterns of important feeding trees will be collected to measure fine-scale changes in fruit abundance. This project will clarify our knowledge of why subgroups form and split, providing a clearer understanding of the factors causing the evolution of a fission-fusion society, and thereby provide important comparative information for the understanding of the evolution of primate social systems. Additionally, it will provide evidence bearing upon the possession of mental maps by primates, and will provide some of the first data on primate understanding of temporal variation in fruit availability.