Meeting Abstract
Sex steroid hormones play critical roles in regulating the complex suite of social and reproductive behaviors in animals. These hormones control behavior via their activity in the brain regions that influence behavior and in the peripheral tissues that produce it, yet few studies have examined how hormones simultaneously interact with brain, “brawn,” and behavior. In this study, we used a group of six species of Caribbean anole lizards to test the hypothesis that species that exhibit higher rates of social behavior will have greater androgen receptor (AR) expression in the brain regions and muscles associated with those behaviors. For each species, we collected behavioral data in the field to quantify the frequency of two behaviors: extension of the dewlap (a throat fan used in aggressive and courtship displays) and copulation. We then quantify AR expression via immunofluorescence in two muscles: the ceratohyoid (the jaw muscle responsible for dewlap extension) and the retractor penis magnus (the tail muscle responsible for retracting the hemipenes after copulation); and in three brain regions that underlie social behavior in anoles (the ventromedial hypothalamus, pre-optic area, and amygdala). Preliminary data indicate that anole species vary in AR expression in the muscles underlying social display, and suggest that this variation is associated with the behavioral frequencies of these displays. This study will be among the first to examine AR expression in multiple tissues associated with behavior, and to do so in an explicitly evolutionary context.
