Meeting Abstract
Cooperative breeding behavior is a paradoxical behavior wherein some individuals forego breeding to help raise the offspring of other individuals. In many cooperatively breeding species, individuals tend to help raise related offspring, thus increasing their own fitness indirectly; however, even within these systems, considerable variation exists in helping behavior among individuals that cannot be explained by relatedness. Here, we predicted developmental experience may help explain some of this variation. In particular, we focused on developmental stress hormones which have been shown to be predictive of adult morphology, physiology, and behavior in other species. Using the obligate cooperative breeding chestnut-crowned babbler (Pomatostomus ruficeps), we measured feather corticosterone in chicks just before fledging. We predicted feather corticosterone would be related both to developmental environment (specifically, number of helpers) and to adult cooperative behavior. Helpers in this species help by provisioning nestlings and, unsurprisingly, the number of helpers is positively related to the amount of food provisioned to each brood. Surprisingly, we found a positive relationship between feather corticosterone and helper number. Analyses between feather corticosterone and adult provisioning behavior are still ongoing. However, identifying the proximate mechanisms that drive variation in cooperative behavior may also begin to explain the ultimate mechanisms by which cooperative breeding has evolved.
