Is locomotor performance optimized at preferred body temperature? A study of Liolaemus pictus argentinus from northern Patagonia, Argentina

KUBISCH, ERIKA; FERNÁNDEZ, JIMENA; IBARGÜENGOYTÍA, NORA

JOURNAL OF THERMAL BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2011 vol. 36 p. 328 - 333

0306-4565

We studied the relationship between performance and temperature in Liolaemus pictus argentinus, from the Andean-Patagonian forest, Argentina. We determined the running speed in long and sprint runs at four different body temperatures, the panting threshold, and minimum critical temperature. The results are discussed in relation to body temperature in the field and thermal preference in the laboratory (Tpref). L. p. argentinus achieved higher speed in sprint runs than in long runs at all temperatures. Pregnant females were at a disadvantage compared to other individuals when running long distances, but in sprint runs they were able to run as fast. In long runs, the performance optimal temperature for L. p. argentinus (To; 30.7 ºC) was below to the central 50% of the all body temperatures selected in the laboratory (set-point range of Tpref = 34.6-37.9 ºC), but similar to the mean field body temperature (32.13 ºC). However, in sprint runs the To (36.3 ºC) was within the set-point range of Tpref. The panting threshold mean (42.8 ºC) and the mean minimum critical temperature (6.91 ºC) were similar to those of others liolaemids. The results are evidence that L. p. argentinus is well-adapted to their current environment and has a Tpref that allows them to achieve maximal performance in the most frequently used and probably the most important run type, the sprint run. Keywords: Thermal sensitivity, panting threshold, minimum critical temperature, cold environment, Liolaemidae.