Effects of progressing age on energy balance, sociality and health in wild female Assamese macaques (Macaca assamensis)

随着人类年龄的增长，他们减少了社交活动，在选择伴侣时变得越来越挑剔，他们更喜欢有价值的关系，而不是没有意义的关系。这种社会-情感的选择性被归因于老年人有限的时间视角。在没有意识到有限时间的情况下，社会活动的减少和社会伴侣的数量也是非人类灵长类动物年龄增长的特征。我们认为，随着年龄的增长，社会活动的减少是由于与年龄相关的觅食性能、能量摄入量和能量平衡的下降而导致的能量限制。精力紧张和社交能力下降构成了精神和社会压力的来源，预计会影响生理压力水平，进而影响一个人的S健康。在这个项目中，我们对面临能量供应显著自然变化的野生阿萨姆猕猴种群进行了长期研究，我们结合了年龄对食物摄入量和能量预算的影响、社会融合的衡量标准、营养和社会压力的生理衡量标准与健康指标，特别是肠道微生物群落和非特异性免疫标记物的数据。这个项目有三个主要目标。首先，我们将补充一些关于自然生态条件下野生种群行为老年学的研究，这些研究使我们能够将能量限制作为限制社会活动的一个重要因素，但很少被研究。其次，我们的目标是通过同时测量非特异性应激标志物(糖皮质激素)和营养应激标志物(甲状腺激素)来分离老年人对营养和社会应激源的生理反应。最后，我们的目标是将与年龄有关的能量限制、生理应激反应和社会融合措施与健康指标联系起来。总而言之，这些数据将有助于全面理解能量因素对社会活动和选择性的作用，并将为人类行为老年学的研究提供信息。

As humans age they decrease their social activity and become increasingly selective in their choice of partners favoring valuable relationships over less meaningful ones. This socio-emotional selectivity has been attributed to the limited time perspective of elderly humans. A decline in social activity and number of social partners are also characteristics of increasing age in nonhuman primates in the absence of awareness of limited time. We propose that the declining social activity with progressing age is driven by energetic constraints due to age-related decreases in foraging performance, energy intake and energy balance. Energetic constraints and decreasing sociality pose energetic and social stressors and are expected to influence physiological stress levels which in turn impact an individual´s health. In this project on our long-term study population of wild Assamese macaques facing pronounced natural variation in energy availability, we combine data on age effects on food intake and energy budget, measures of social integration, physiological measures of nutritional and social stress with indicators of health, specifically the gut microbial community and a non-specific immune marker. This project has three main goals. First, we will add to the few studies on behavioral gerontology in wild populations under natural ecological conditions which enables us to integrate energetic constraints as an important but rarely investigated factor limiting social activity. Second, we aim to separate physiological responses to nutritional and social stressors experienced by aged individuals by simultaneously measuring a non-specific stress marker (glucocorticoids) and a nutritional stress marker (thyroid hormone). Lastly, we aim to link age-related energetic constraints, physiological stress responses and measures of social integration to health indicators. Together, these data will contribute to a comprehensive understanding of the role of energetic factors on social activity and selectivity with increasing age and will inform studies on human behavioral gerontology.