PARENT SESSION
Oral Session #56: Spatial Ecology: Pattern,movement,dispersal.
Presiding: G. Hartvigsen
Wednesday, August 7. 8:00 AM to 11:30 AM. Grand Ballroom West, Radisson.

Implications of spatial and movement patterns for gene flow in black rat snakes.

Blouin-Demers, Gabriel^*,1, Weatherhead, Patrick², ¹ The Ohio State University, Columbus, Ohio² University of Illinois at Urbana-Champaign, Champaign, Illinois

ABSTRACT- Gene flow is fundamental to evolutionary processes, but knowledge about movements of individuals and their offspring necessary for gene flow is scant. We investigated potential ecological components of genetic connectivity by radio-tracking 82 black rat snakes. Because adult black rat snakes are highly faithful to their hibernacula, gene flow between hibernacula populations has to occur through mating between members of different hibernacula or through juvenile dispersal. The mean distance between nearest-neighbor hibernacula was 811 m, which was less than the mean distances that reproductive males and females were found from their hibernacula during the mating season. Estimates of mean maximum distances from hibernacula indicated that reproductive females encountered males that were on average from two hibernacula away from their own hibernaculum. Both males and females appeared to actively contribute to gene flow by moving more and increasing their distance from their hibernacula during the mating season. In addition, on average females nested closer to a hibernaculum other than the one they attended, thereby potentially increasing the likelihood that their offspring join hibernacula other than their mothers'. Thus, spatial and movement patterns of male and female black rat snakes are consistent with genetic evidence of extensive out-breeding among local hibernacula populations.

KEY WORDS: black rat snake, Elaphe obsoleta, Gene flow, dispersal