The Role of the Amygdala in Nonbreeding Aggression in Male Green Anole Lizards, Anolis carolinensis.

Aggression is a set of hostile behaviors expressed to defend and/or obtain resources. Although a social behavior network (SBN) has been postulated to explain the neural mechanisms underlying aggression, the extent of behavioral modulation by specific brain regions remains unclear. Additionally, the regulation of the SBN during the nonbreeding season (NBS) in seasonal breeders that express territorial aggression is still unknown.

Melatonin treatment during the breeding season increases testosterone in male green anole lizards (Anolis carolinensis).

Melatonin is a natural hormone that regulates seasonal behaviors in vertebrates by binding to its receptors (MT1 and MT2). Specifically, high levels of melatonin are associated with short photoperiods, often coinciding with the non-breeding season, meaning that melatonin may inhibit seasonal reproduction. Green anole lizards (Anolis carolinensis), have large, active gonads, increased levels of testosterone and estradiol, and increased reproductive behaviors during the breeding season.