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

Publisher Website
Google Scholar
Abstract
Whether male garter snakes require intact vomeronasal or olfactory systems to detect the pheromone that triggers the chin-pressing behavior of courtship was determined. Male garter snakes (Thamnophis radix) with testosterone propionate pellets implanted s.c. 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; control surgeries were performed on a 3rd. After postoperative testing the heads of the snakes were histologically processed for lesion verification. All snakes in the olfactory nerve cut and control groups courted after surgery, and 3 snakes in each group copulated. More than half 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. Male garter snakes without functional olfactory systems do court and mate normally, but male garter snakes without functional vomeronasal systems exhibit no courtship responses.