HAN, B.A.; KATS, L.B.; POMMERENING, R.C.; MURRY, M.A.; KIESECKER, J.M.; BLAUSTEIN, A.R.: Avoidance of ultraviolet radiation (UV-B) by two species of diurnal poison-dart frogs.

Negative effects of ultraviolet-B (UV-B) radiation on amphibians have been reported in several studies. UV-B radiation negatively impacts both amphibian eggs and larvae. However, few studies have examined the sensitivity of adult amphibians to UV-B radiation. Using both field experiments and field observations we found that two species of diurnal poison-dart frogs (Dendrobates pumilio, D. auratus) consistently preferred areas with low levels of UV-B radiation. Field enclosures were divided in half by two filters. One filter blocked UV-B radiation while the other transmitted UV-B. The filters did not produce significant differences in either substrate or air temperatures in the enclosures. Both species of frogs spent significantly more time under the UV-B blocking filter. In field observations, vocalizing D. pumilio were found at locations with significantly lower levels of ambient UV-B than random locations throughout the rainforest. A recent study has found increasing levels of UV-B radiation in Central America. Therefore, UV-B radiation may be an important selection pressure on these diurnal tropical frogs.