Effects of ultraviolet-B radiation on metamorphic traits in the common frog Rana temporaria

Abstract

Effects of ultraviolet-B (UV-B) radiation on amphibian embryonic and larval development have been investigated in a number of studies, but the effects on later life-stages (metamorphosis) have received less attention. Hence, the effects of UV-B radiation treatments (control (no UV-B), normal and 26% enhanced levels of UV-B) on the development of the common frog Rana temporaria embryos from fertilization until metamorphosis were investigated. Survival until metamorphosis was significantly higher among individuals exposed to normal, as compared to individuals sheltered from, UV-B or those exposed to enhanced levels of UV-B radiation. There were no effects of normal or enhanced levels of UV-B radiation on the frequency of developmental anomalies. However, UV-B radiation delayed the timing of metamorphosis in a dose-dependent fashion, and the individuals from the normal and enhanced UV-B treatments metamorphosed at smaller size than those raised in the absence of UV-B radiation. These results suggest that UV-B radiation experienced through embryonic and larval stages can have negative effects on the growth and development of R. temporaria. Delayed metamorphosis at reduced size is also likely to lower the fitness during later life-stages.