Thermal biology and locomotor performance of the Andean lizard Liolaemus fitzgeraldi (Liolaemidae) in Argentina

Abstract

Ectotherms thermoregulate to maintain their body temperature within the optimal range needed for performing vital functions. The effect of climate change onlizards has been studied as regards the sensitivity of locomotor performance toenvironmental temperatures. We studied thermoregulatory efficiency and locomotor performance for Liolaemus fitzgeraldi in the Central Andes of Argentina.We determined body temperature, micro-environmental temperatures and operative temperatures in the field. In the laboratory, we measured preferred temperatures and calculated the index of thermoregulatory efficiency. We estimated thethermal sensitivity of locomotion by measuring sprint speed (initial velocity andlong sprint) and endurance at five different body temperatures. Body temperaturewas not associated with either micro-environmental temperature, nor did it showdifferences with preferred temperatures. Thermoregulatory efficiency was moderate (0.61). Initial velocity and long sprint trials showed differences at differenttemperatures; however, endurance did not. Moreover, the optimal temperaturesfor the performance trials showed no significant differences among themselves.We conclude that Liolaemus fitzgeraldi has thermal sensitivity in locomotor performance with respect to body temperature and that it is an eurythermic lizardthat experiences a large variation in body temperature and that has thermal flexibility in the cold