1School of Anthropology, University of Arizona, 2Centre ValBio, Ranomafana, Madagascar, 3Developmental Biology Program, Institute of Biotechnology, University of Helsinki, 4Anthropology, Stony Brook University
Thursday Evening, Park Concourse
The cort-fitness hypothesis proposes that individuals with high cortisol levels will experience reduced fitness because of the maladaptive effects that prolonged, elevated levels can have on long-term functions. Previous research in primates indicates that habitat disturbance can result in elevated levels, or a muted response with little fluctuation. Furthermore, habitat disturbance may differentially impact species with different diets. We investigated whether cortisol levels in a folivorous lemur differ in disturbed (n=2) and undisturbed (n=1) habitats. We predicted that, in the disturbed sites, mean cortisol levels would be higher, and the response to environmental challenge (increased food scarcity and aridity) would be stronger. 1059 fecal samples from 10 females and 11 males were analyzed using solid phase extraction and enzyme immunoassay. We used linear mixed models with fixed factors age, sex, site, and group, and random factors monthly rainfall and food availability. Site differences approached significance, F(2,49.28)=3.012, P=0.058. Fecal cortisol levels in the most disturbed site were significantly lower than in the undisturbed site (P=0.018), contrary to findings for folivorous monkeys (Alouatta pigra), but similar to findings for frugivorous lemurs (Eulemur rubriventer). These results confirm that lower cortisol levels can occur in disturbed habitats, and that a muted response may be adaptive in a harsh environment.
Supported by NSF-BCS721233.