Understanding the ecological and social factors that influence group size is a major focus of primate behavioural ecology. Studies of species with fission–fusion social organizations have offered an insightful tool for understanding ecological drivers of group size as associations change over short temporal and spatial scales. Here we investigated how the fission–fusion dynamics of spider monkeys ( Ateles geoffroyi ) at Runaway Creek, Belize were affected by fruit availability. When males and females were analyzed together, we found no association between fruit availability and subgroup size. However, when females were analyzed separately, we found that when fruit availability increased, so did subgroup size. In all analyses, higher fruit availability did not influence subgroup spatial cohesion. Our results point to the complexity of understanding grouping patterns, in that while ecological factors make groups of specific sizes advantageous, social factors also play an important determining role.

中文翻译：

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水果供应与蜘蛛猴的裂变融合动力学有着复杂的关系

了解影响群体规模的生态和社会因素是灵长类行为生态学的一个主要焦点。对具有裂变融合社会组织的物种的研究为理解群体规模的生态驱动因素提供了一个有见地的工具，因为关联在短期和空间尺度上发生变化。在这里，我们调查了伯利兹 Runaway Creek 的蜘蛛猴 (Ateles geoffroyi) 的裂变融合动力学如何受到水果供应的影响。当一起分析男性和女性时，我们发现水果可用性与亚组大小之间没有关联。然而，当单独分析雌性时，我们发现当水果可用性增加时，亚组大小也会增加。在所有分析中，较高的水果可用性不影响亚组空间凝聚力。