The relationship of coping style and social support variation to glucocorticoid metabolites in wild olive baboons (Papio anubis)

Social support, via investment in relationships of importance with others, is often emphasized as a pathway towards mediating stress. The effectiveness of social support, however, can be altered by personality differences, but the physiological consequences of such covariation are still poorly explored. How do individual differences in the functioning of the stress response system mediate access to, and use of, social support? To examine this dynamic, we investigated glucocorticoids as a biomarker of energetic activation that may also be activated by chronic psychosocial stress. For this purpose, we studied a wild anthropoid primate, i.e. the olive baboon (Papio anubis), for 17 months, in Laikipia District, Kenya. We measured biomarkers of energetic activation, i.e., fecal glucocorticoid metabolites (fGCms), to address whether individual differences in stress coping and social support were associated with variation in hormone levels across a period from 2018 to 2019. We found evidence for an association between social support and fGCm concentrations. This association had a discernable interaction between sex and social support: we found a negative association in male baboons, relative to females—who did not have a pronounced effect. Our findings emphasize the importance of social support in male baboons. The cost of not having diverse bonds, has been downplayed in male baboons.

Methods
Data were collected from two groups of in situ (wild) olive baboons, in Laikipia, Kenya. An experimental paradigm was used to collect coping style scores over a 17-month period; behavioral observations were collected with focal follows and ad libitum sampling, over a 17-month period; fecal samples were collected over a nine month period; daily rainfall and min/max temperature were collected each day that fecal sampling was ongoing. Shannon Weiner's Diversity Indices as a metric of social support calculated based on grooming dynamics across the relevant project period. Rank was calculated from social displacements. Rainfall and temperature were averaged across the two days, relative to each fecal sample's collection. Fecal sample hormones were extracted and assayed using RIAs. More details are in the associated manuscript.

社会支持（Social Support）常被视为缓解压力的重要途径，即通过投入经营与他人的重要人际关系。然而，社会支持的有效性会因个体人格差异而发生改变，但这种共变关系所带来的生理后果仍鲜有研究。应激反应系统功能的个体差异，是如何调节个体获取并利用社会支持的过程的？为探究这一动态机制，我们将糖皮质激素（glucocorticoids）作为能量激活的生物标志物展开研究——这类激素亦可因慢性心理社会应激而被激活。为此，我们在肯尼亚莱基皮亚郡（Laikipia District）对野生类人猿灵长类动物——橄榄狒狒（Papio anubis）开展了为期17个月的研究。我们以粪便糖皮质激素代谢物（fecal glucocorticoid metabolites, fGCms）作为能量激活的生物标志物，旨在探究2018至2019年间，个体的应激应对方式与社会支持的差异是否与激素水平的变化存在关联。我们发现社会支持与粪便糖皮质激素代谢物浓度之间存在关联。该关联存在显著的性别与社会支持交互效应：相较于未表现出明显效应的雌性狒狒，雄性狒狒体内呈现出负相关关系。我们的研究结果凸显了社会支持对雄性狒狒的重要性，而此前学界对雄性狒狒缺乏多样化社会联结所付出的代价重视不足。

研究方法
本研究的数据采集自肯尼亚莱基皮亚地区的两个野生（in situ）橄榄狒狒种群。我们通过实验范式在17个月的周期内采集了应激应对风格得分；同时采用焦点取样（focal follows）与随意取样（ad libitum sampling）两种方式，在同样为期17个月的周期内完成了行为观察；粪便样本的采集周期为9个月；在粪便采样开展的每日，我们同步记录了当日降雨量以及最高、最低气温。我们基于研究周期内的理毛行为动态，计算得到香农-威纳多样性指数（Shannon Weiner's Diversity Indices）作为社会支持的衡量指标。社会地位等级通过社交移位行为的记录计算得出。针对每一份粪便样本的采集时间，我们取其前后两日的降雨量与气温平均值作为环境指标。粪便样本中的激素采用放射免疫分析法（RIAs）进行提取与检测。更多研究细节可参见相关研究论文。