Roles of the vomeronasal and olfactory systems in courtship behavior of male garter snakes.

Studied whether male garter snakes required intact vomeronasal or olfactory systems to detect the pheromone that triggers the chin-pressing behavior of courtship. Male garter snakes with testosterone propionate pellets implanted sc were tested for courtship displays with estradiol-benzoate-treated females. Three groups of 10 males were formed from snakes exhibiting strong courtship responses. Bilateral olfactory nerve cuts were attempted on 1 group, vomeronasal nerve cuts on a 2nd, and control surgeries on a 3rd. All snakes in the olfactory nerve cut and control groups courted after surgery, and 3 snakes in each group copulated. More than half of the snakes in the olfactory nerve cut group had complete nerve cuts. Nine of the 10 snakes in the vomeronasal nerve cut group exhibited no courtship responses after surgery. The 1 snake in this group that courted was the only snake in which intact vomeronasal nerve fascicles were observed. Data indicate that male garter snakes without functional olfactory systems do court and mate normally, but that male garter snakes without functional vomeronasal systems exhibit no courtship responses. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)