Fecal glucocorticoids as indicators of metabolic stress in female Sykes' monkeys (C ercopithecus mitis albogularis)

• Published in: Hormones and behavior Vol. 58; no. 4; pp. 685 - 697
• Main Authors: Foerster, Steffen, Monfort, Steven L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.09.2010; Elsevier; Elsevier BV
• Subjects: Animal behavior; Animals; Azadirachta indica; Behavioral psychophysiology; Biological and medical sciences; Biomarkers - analysis; Biomarkers - metabolism; Cercopithecus - metabolism; Cercopithecus mitis; Feces; Feces - chemistry; Feeding Behavior - physiology; Feeding ecology; Female; Fundamental and applied biological sciences. Psychology; Glucocorticoids; Glucocorticoids - analysis; Glucocorticoids - metabolism; Health Status Indicators; Hormones and behavior; Individual differences; Individuality; Metabolic stress; Metabolism; Monkey Diseases - diagnosis; Monkey Diseases - metabolism; Monkeys & apes; Proximate causes; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rank effects; Reproduction - physiology; Social behavior; Steroids; Stress response; Stress, Physiological - physiology; Tamarindus indica; Temporal variation; Time Factors; Cercopithecus mitis; Social behavior; Temporal variation; Rank effects; Glucocorticoids; Individual differences; Proximate causes; Metabolic stress; Feeding ecology; Feeding behavior; Monkey; Ecology; Glucocorticoid; Time variation; Indicator; Stress; Feeding; Vertebrata; Mammalia; Social interaction; Animal; Interindividual comparison; Primates; Female
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2010.06.002

Because of their mediating role in the stress response and potential effects on fitness, glucocorticoid (GC) hormones are increasingly used to assess the physiological costs of environmental and behavioral variation among wild vertebrates. Identifying the proximate causes of GC variation, however, is complicated by simultaneous exposure to multiple potentially stressful stimuli. Here, we use data from a partially provisioned social group of Sykes' monkeys to evaluate the effects of potential psychological and metabolic stressors on temporal and individual variation in fecal GC (fGC) excretion among 11 adult females. Despite high rates of agonism over provisioned foods fGCs declined during periods of high provisioning frequency when fruit availability was dominated by neem ( Azadirachta indica), an item requiring great feeding effort. Provisioned foods did not prevent fGC increases when availability of the most preferred main fruit item, tamarind ( Tamarindus indica), declined drastically. Although rank-related differences in access to provisioned foods and rates of agonism did not lead to an overall effect of rank on fGCs, low-ranking females excreted more fGCs than high-ranking females during a period of high provisioning intensity and low fruit availability. The emergence of this rank effect was associated with elevated feeding effort in all females, a greater access to provisioned items by high-ranking females, and a higher proportion of time spent moving in low-ranking females. Our findings suggest that metabolic stressors were the primary determinants of both temporal and individual variation in fGCs, indicating potential fitness benefits for high-ranking females when food availability is limited.