Compensation for exposure to increased environmental temperatures is costly in a montane, desert lizard

Extreme weather events will increase in frequency and intensity with climate change. Physiological and behavioral modulation during these extreme climatic events will likely facilitate persistence of ectothermic species, but these compensatory responses may be costly. We transplanted greater short-horned lizards (Phrynosoma hernandesi) from a cool, high-elevation site to a warm, low-elevation site to quantify the costs of acute temperature increases. We predicted that transplanting lizards to the warmer environment would increase mass loss relative to Control lizards by increasing DEE, thermal tolerance, and circulating CORT and altering spatial ecology and basking behavior. We found that transplanted lizards experienced a significant decline in mass, but this decline was not a result of increased energetic expenditure or circulating CORT. Rather, this loss appeared to be driven by changes in basking behavior and space use. Our data suggest changes in thermoregulatory behavior alleviated the direct effects of a greater environmental thermal load. However, these behavioral changes were associated with their own costs, likely due to limitations on resource acquisition resulting from decreases in basking and foraging activities. Our research suggests compensation for increased temperatures does not necessarily eliminate the costs of rapid environmental change.