Meeting Abstract
Brown anole lizards pose a perplexing example of neural steroid regulation in reproductive behavior. While testosterone is perceived to be the crucial steroid in male aggression, the low baseline levels of testosterone in brown anoles are mismatched with their high levels of reproductive behaviors. Previous steroid manipulations in brown anoles generally showed variability in changes to behavior but suggested that an increase in testosterone did not directly increase aggression. This contributes to the question of how brown anoles support high aggression with low testosterone. Past studies with aromatization inhibitors were equivocal, making the role of estrogens in male sexual behavior unclear. Given that androgen levels are typically lower, it is feasible to consider estrogens as being the primary mediator in sexual behavior as in some other vertebrates. The process of aromatization converts androgens into estrogens, and the low levels of testosterone may suggest that estrogens play a larger role. To further understand the mechanism of reproductive behaviors in A. sagrei, experimentation with the factors of the aromatization process was conducted. We exposed 40 male lizards to either flutamide (anti-androgen), estradiol, fadrozole (aromatase inhibitor) or control treatments (10 in each group) for 5 days. We then conducted behavioral trials through 20-minute side-by-side introductions of both an intruding male for aggression and (separately) a female for courtship stimulus. We expected that flutamide and fadrozole would decrease reproductive behaviors. We describe how each treatment helps understand the role of androgens and estrogens in regulating male aggression and courtship behavior in brown anoles.
