Meeting Abstract

P1.26  Jan. 4  Variation in desiccation tolerance among red-eared slider turtle populations LIGON, D.B.*; GREGORY, G.; KAZMAIER, R.; LOVERN, M.B.; Oklahoma State University; Oklahoma State University; West Texas A&M, Canyon; Oklahoma State University day.ligon@okstate.edu

The red-eared slider turtle (Trachemys scripta) is common throughout the southeastern United States, ranging north to Illinois and west into New Mexico and the Texas panhandle. Water availability varies across its range, and the extent of terrestrial activity by this putatively aquatic species tends to be high where water is scarce. We predicted that T. scripta from xeric habitats would be more tolerant of drought conditions than populations in more mesic areas. We tested this hypothesis by comparing physiological responses to desiccation of two populations inhabiting dramatically different habitats. Turtles from dry chaparral habitat in west Texas tended to exhibit traits that made them better adapted to dry conditions than turtles from eastern Oklahoma where water is abundant. During laboratory-based water deprivation trials turtles from Texas exhibited lower rates of evaporative water loss, lower resting metabolic rates, lower hematocrit and slower accumulation of plasma solutes. Our results suggest that, either by genetic adaptation or long-term physiological acclimatization, populations of this species vary in their capacity for drought tolerance.