Meeting Abstract

85.4  Sunday, Jan. 6  Limited thermal acclimation capacity in a salamander, Desmognathus brimleyorum YOUNG, V.KH.**; GIFFORD, M.E.; Clemson Univ.; Univ. Arkansas, Little Rock vkhilli@clemson.edu

Temperature is a critical factor impacting the fitness of ectotherms. Previous studies have indicated that many ectotherms have the ability to adjust their physiological capabilities to cope with variation in their thermal environment. Theories of optimal acclimation predict that individuals experiencing thermal conditions that fluctuate widely will exhibit physiological traits that are less sensitive to temperature than those individuals experiencing stable thermal conditions. We tested this prediction by studying acclimation of swimming performance, metabolic rate, and critical thermal maximum in the salamander Desmognathus brimleyorum. Salamanders from each of five populations across the species range in Arkansas, USA were assigned to either a constant or variable temperature treatment in the lab. Following a two-month period of acclimation, each salamander was subjected to swimming speed trials at each of seven temperatures between 2 and 30°C. Each trial was recorded using a high-speed camera and velocity data were collected via video analysis. Metabolic rates for individuals were measured using flow-through respirometry and recorded over four temperatures between 5 and 20°C. Our results indicate that adult D. brimleyorum do not acclimate swimming performance to alternate thermal environments. However, limited capacity for thermal acclimation of metabolism and thermal tolerance was evident in this study. Interestingly, the majority of variance detected in this experiment resulted from differences among populations. We also discuss interpopulation variation in physiological traits and possible sources of this variation.