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Yasuni国家公园长毛蜘蛛猴（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，一个社区的所有成员很少同时在同一个地方。相反，社区的子集（子组）是临时关联的，并且经常改变关联。很少有研究解决是什么导致个人从这些亚群体中分裂出来或加入这些亚群体。该项目将评估对果树果实数量的预期如何影响子群体的分裂决策，子群体融合的竞争或合作性质，以及子群体的变化在多大程度上受到与食物无关的原因（如社会因素）的影响。为了解释这些问题，这个项目将提供证据，证明蜘蛛猴知道在哪里可以找到觅食的树木，以及何时可以对这些树木进行有利可图的访问。为了实现这些目标，将从黎明到黄昏对成年雌性进行为期两周的跟踪，以收集有关亚群变化和资源使用的数据。此外，还将收集重要食用树的结果模式数据，以测量果实丰度的精细变化。这个项目将澄清我们对亚群体形成和分裂的原因的认识，提供对导致分裂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得性的时间变化的理解的一些第一手数据。

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.