Meeting Abstract

P2.1  Tuesday, Jan. 5  Interspecific Variation in the Female Sexual Attractiveness Pheromone of Garter Snakes UHRIG, E.J.*; CHRISTOPHERSON, Z.; LEMASTER, M.P.; MASON, R.T.; Oregon State University; Western Oregon University; Western Oregon University; Oregon State University uhrige@onid.orst.edu

During the breeding season, female garter snakes produce a sexual attractiveness pheromone composed of a homologous series of saturated and monounsaturated methyl ketones. This pheromone, expressed in the skin lipids of females, elicits courtship behavior from males, who rely extensively on the pheromone for recognition of suitable mates. Utilizing four garter snake species, including two pairs of sympatric species, the current study is designed to investigate whether the chemical profile of the female sexual attractiveness pheromone exhibits interspecific variation. Pheromone samples were collected from females of each species: the red-sided garter snake (Thamnophis sirtalis parietalis) and the plains garter snake (Thamnophis radix), which are sympatric in Manitoba, Canada, as well as the red-spotted garter snake (Thamnophis sirtalis concinnus) and the northwestern garter snake (Thamnophis ordinoides), which are sympatric in Oregon. Chemical analyses revealed significant qualitative variation in the chemical profile of the pheromone between all four species. This dissimilarity was particularly evident within the sympatric groups. These results suggest that the female sexual attractiveness pheromone of garter snakes may function as a mechanism of prezygotic reproductive isolation allowing males to distinguish between conspecific and heterospecific females.