Mitigation of the Effects of Chronic Stress through Social Bonding

在包括人类在内的许多灵长类社会中，个体形成了强大而持久的社会关系，这种社会关系可以通过延长寿命、后代存活率以及最终的繁殖成功率来适应。人们仍然知之甚少的是，社会纽带实现其效果的机制。一种可能性是，由于已知的帮助个人应对压力源的功能，社会关系减轻了慢性压力对健康和生殖的负面影响。但是，日常生活中的社会压力是否以及如何影响灵长类动物社会中的雌性生殖，人们也知之甚少。该项目将通过研究将社会关系的变化与健康和生殖措施联系起来的途径，解决我们在知识方面的上述两个空白。评估应激激素是否介导肠道寄生虫感染的易感性；研究社会压力与生殖生理之间的关系；并评估社会关系是否在喂养竞争中取得成功，从而为繁殖提供能量。该项目的数据将从南非开普半岛的三支chacma狒狒（Papio ursinus）部队收集。该项目的多方面数据将包括行为观察，以记录压力和社会关系的来源；通过非侵入性收集粪便样本测量应激和生殖激素以及肠道寄生虫负荷；收集尿c肽（胰岛素产生的副产品）来测量能量平衡。此外，将进行一项新的野外实验，从随机选择的雌性动物中剔除肠道寄生虫，首次在野生灵长类动物中评估与再次感染时间和强度相关的因素。利用这一综合方法，本研究将对社会行为、应激生理、健康和繁殖之间的联系机制产生新的见解，并有助于阐明灵长类社会中社会纽带的功能。由于狒狒等非人类灵长类动物与人类有许多共同的特征，在研究人类生物学方面很有用，该项目将通过阐明社会压力作为寄生虫感染风险因素的作用，提高对人类进化过程中社会性益处的理解，并具有临床意义。该项目将加强美国和南非之间的机构联系，培训在科学领域代表性不足的学生，并提供有价值的数据和教育资源，以帮助管理和保护灵长类动物。

In many primate societies, including humans, individuals form strong, long-lasting social bonds which can be adaptive, for example, by increasing longevity, offspring survival, and, ultimately, reproductive success. What is still poorly understood are the mechanisms by which social bonds achieve their effects. One possibility is that, because of their known function in helping individuals cope with stressors, social bonds mitigate negative effects of chronic stress on health and reproduction. But whether, and how, daily-life social stress influences female reproduction in primate societies also is poorly understood. This project will address both of the above gaps in our knowledge by examining the pathways connecting variation in social bonds with measures of health and reproduction. It will assess whether stress hormones mediate the susceptibility to intestinal parasite infections; examine the relationship between social stress and reproductive physiology; and evaluate whether social bonds mediate success in feeding competition, and hence, energy available for reproduction. Data for this project will be collected from three troops of chacma baboons (Papio ursinus) in the Cape Peninsula of South Africa.The project's multifaceted data will include behavioral observations to document sources of stress and social bonds; measurement of stress and reproductive hormones, as well as intestinal parasite loads, via non-invasively collected fecal samples; and collection of urinary C-peptide (a byproduct of insulin production) to measure energy balance. Additionally, a novel field experiment will be conducted in which intestinal parasites are eliminated from a random selection of females to assess, for the first time in a wild primate, the factors associated with the timing and intensity of re-infection. Utilizing this comprehensive approach, the research will generate new insights into the mechanisms linking social behavior, stress physiology, health, and reproduction, and help elucidate the function of social bonds in primate societies. Because non-human primates such as baboons share many traits with humans and are useful in studying aspects of human biology, this project will improve understanding of the benefits of sociality during human evolution and carry clinical implications by elucidating the role of social stress as a risk factor for parasite infections. The project will strengthen institutional ties between the U.S. and South Africa, train students underrepresented in science, and provide valuable data and educational resources to aid in management and conservation of primates.