Thermal acclimation and metabolism in the gray-bellied salamander, Eurycea multiplicata griseogaster (plethodontidae)

Abstract

1. 1. Oxygen consumption rates of gray-bellied salamanders, Eurycea multiplicata griseogaster, were measured at acclimation temperatures of 5, 10, 15, 20 and 25°C, and acutely at plus and/or minus 5°C. 2. 2. Virtually complete metabolic acclimation (Q 10 = 1.1) occurred between 5°C (13.8 μl O 2 g −1 hr −1) and 10°C (14.8 μl O 2 g −1 hr −1). 3. 3. Partial metabolic acclimation (Q 10 = 1.6) occurred between 5 and 15°C (15.8 μl O 2 g −1 hr −1). 4. 4. Acclimation was not apparent at 20°C (46.5 μl O 2 g −1 hr −1) or 25°C (76.0 μl O 2 g −1 hr −1) as acclimation Q 10's for 15–20°C and 20–25°C were 4.5 and 2.7 respectively. 5. 5. Low and partial metabolic sensitivity to acutely-lowered temperatures (−5°C) occurred in 10°C acclimated salamanders for 10-5°C (14.8 vs 13.3 μl O 2 g −1 hr −1 Q 10 = 1.2), for 15-10°C in the 15°C acclimated group (21.8 vs 15.8 μl O 2 g −1 hr −1), for 20-15°C (46.5 vs 47.3; Q 10 = I) in the 20°C acclimated group and in 25°C acclimated salamanders for 25-20°C (76.0 vs 54.7 μl O 2 g −1 hr −1; Q 10 = 1.9). 6. 6. Metabolic acclimation and insensitivity to temperatures in the 5–15°C range were consistent with the relatively low ( X ̄ = 13° C ) and stable thermal conditions in their ground waterspring habitats. 7. 7. High metabolic sensitivity between 15 and 20°C (Q 10 = 4.5), and insensitivity to acute 5°C drops in temperature in 20 and 25°C acclimated salamanders may be adaptive, providing recently-transformed adults with metabolic capability to disperse rapidly overland to new aquatic sites.