Doctoral Dissertation Improvement: The Impact of Seasonal Variation in Food Resources and Ranging Patterns on the Reproductive Physiology and Behavior of Female Spider Monkeys

在人类和类人猿中，已经证明女性的生殖周期是根据能量平衡而变化的。特别是，研究表明，当饮食质量差或持续体力消耗时，卵巢类固醇（如雌激素和黄体酮）的水平会下降，这可能导致不孕。但是，尽管这种模式在人类及其近亲身上已经有了记载，但所谓的生态能量学假说（EEH）尚未在任何其他非人类灵长类动物身上得到验证。蜘蛛猴为检验这一假设提供了一个极好的模型，因为与许多新大陆猴相比，它们与类人猿有许多共同的相关特征，包括非季节性繁殖、更广泛的生殖参数和高度的食物专业化。先前对蜘蛛猴的研究已经证明了一种一致的模式，即雌性蜘蛛猴在成熟果实丰度低的时候无法怀孕。然而，到目前为止，还没有研究充分证明饮食、活动水平和生殖状况之间存在明确的联系。本研究测试了巴拿马巴罗科罗拉多岛自由放养的黑爪蜘蛛猴的EEH。通过将雌性蜘蛛猴觅食行为数据与当地水果丰度和营养含量的现有信息相结合来评估饮食质量。然后将这些值与已知雌性繁殖周期的月变化进行比较。本研究的结果有助于更好地理解蜘蛛猴的生殖生物学和行为，并提高我们对资源季节变化如何影响灵长类动物进化的理解。此外，通过关注对蜘蛛猴重要的特定果实物种，这项研究有可能为未来的保护管理决策提供信息。最后，这个博士论文研究项目也有助于一位女性西班牙裔研究生的专业发展，并将涉及与拉丁美洲研究人员的合作。

In both humans and great apes it has been demonstrated that a female's reproductive cycle varies in response to energy balance. In particular, research has shown that levels of ovarian steroids, such as estrogen and progesterone, fall when diet quality is poor or in response to sustained physical exertion, potentially resulting in infertility. But while this pattern has been documented in humans and their closest relatives, the so-called ecological energetics hypothesis (EEH) has not been tested in any other non-human primate. Spider monkeys provide an excellent model to test this hypothesis because in contrast to many New World monkeys, they share a number of relevant traits with the great apes including non-seasonal breeding, extended reproductive parameters, and a high degree of food specialization. Previous research on spider monkeys has demonstrated a consistent pattern whereby females fail to conceive during times when ripe fruit abundance is low. To date, however, no study has adequately demonstrated a clear link between diet, activity levels, and reproductive condition. This research tests the EEH in free ranging black-handed spider monkeys on Barro Colorado Island, Panama. Diet quality is assessed by combining female spider monkey foraging behavior data with available information on local fruit abundance and nutritional content. These values are then compared to monthly changes in the reproductive cycles of known females. Results from this study contribute to a better understanding of spider monkey reproductive biology and behavior and improve our understanding of how seasonal changes in resources impact primate evolution. Furthermore, by focusing on specific fruiting species important to spider monkeys the research has the potential to inform future conservation management decisions. Finally, this doctoral dissertation research project also contributes to the professional development of a female, Hispanic graduate student and will involve collaboration with Latin American researchers.