1Department of Anthropology, William Peace University, 2Department of Anthropology, University of Florida
Friday All day, Plaza Level
Physiological mechanisms are best understood in their ecological and evolutionary contexts. The inexorable dynamic between an organism’s behavior and its underlying mechanisms, however, is most frequently studied in a captive setting meant to control for natural variation. For a few taxa (namely rodents and primates), laboratory studies have assessed the importance of social relationships in the management of stress but there is a noticeable lack of corroborative field data from wild populations. Using brown capuchins (Cebus apella) as our study system, we studied fine-scaled social behavior of individual females (n=7) and tested hypotheses regarding the stress hormone cortisol and female social relationships. As the relationships of female C. apella in Raleighvallen, Suriname are best described as transient and situation-dependent, do the shifts in female social behavior co-vary with physiological stress?
Overall, female glucocorticoid concentrations were not associated with rates of affiliative behavior or with monthly shifts in social relationships. Emergent patterns, however, provide indication of the social mediation of female stress: (1) females received more grooming from strongly bonded troopmates during periods of elevated stress, and (2) an inverse association between female cortisol levels and their grooming of adult males (after controlling for rank) further supports our previous finding that, despite being classified as a female-bonded species, females in this population are more closely bonded to males than to females. These intriguing patterns implicate the potential stress-reducing effects of a strengthened social relationship and provide a framework for future studies regarding the hormonal mechanisms driving sociality.
This study was funded in part by the U.S. National Science Foundation, grant numbers SBR-9722840, BCS- 0078967, and BCS-0352316 awarded to S.B, and NIH grant RR000167.