Thermal dependency of calling performance in the eurythermic frog Colostethus subpunctatus

Only a few species of frogs, represented in four families (Bufonidae, Dendr obatidae, Hylidae, and Leptodactylidae), inhabit elevations above 3000 in i n the tropical Andes, an environment that is characterized by dramatic ther mal fluctuations. This degree of thermal variation forces Andean frogs to b e eurythermic. One species in particular, Colostethus subpunctatus (family Dendrobatidae), is intriguing because it remains active year-round, calls f rom da vn to dusk, and experiences temperatures during calling activity tha t range from 6 C to more than 25 C. This frog, therefore, represents an exc ellent model for studding the effects of temperature on natural behavior in ectothermic vertebrates. In this study, we tested the hypothesis that eury thermy is associated with thermal independence of behavioral performance in C, subpunctatus. We recorded and analyzed vocalizations of more than 50 ca lling males from populations at 3500 in and 2000 m and at various temperatu res. At least nine calls from each individual were selected at random, and characteristics, including calling rate, call duration, and peak frequency, were analyzed. Most temporal parameters were indeed affected by temperatur e, although thermal sensitivity was low. Some temporal and all spectral par ameters exhibited interpopulational differences.