Thermal dependency of field locomotor and vocal performance of high-elevation anurans in the tropical Andes

To investigate whether ambient temperature constrains behavioral performance in high-elevation anurans I studied the thermal dependency of field calling rate and locomotor performance of four Colombian Andean frogs at 2900-3500 m (Atelopus sp. nov., Colostethus sabpunctatus, Eleutherodactylus bogotensis, and Hyla labialis), and compared them with low-elevation (<350 m) congener species (A. varius, C. falamancae, E. diastema, and H. microcephala). Apparently low temperatures constrain only high levels of sustained performance. Body temperature explained 40% of the variance in calling rate of high-elevation frogs that call vigorously (H. labialis and C. subpunctatus), but did not affect the lower calling rates of A. sp. nov. and E. bogotensis. High-elevation frogs in the genera Eleutherodactylus, Atelopus, and Colostethus may exhibit less energetically demanding vocal behaviors than low-elevation congenerics. Both high-elevation and low-elevation frogs moved at low speeds with sporadic bursts of activity. Body temperature did not correlate with the time, speed, or distances that high-elevation frogs moved, which were similar to those of low-elevation congenerics. Reliance on glycolysis, presumably less sensitive to temperature than aerobic metabolic pathways, may partially explain the thermal independence of field locomotion patterns in high-elevation anurans.