Avoidance of ultraviolet-B radiation in frogs and tadpoles of the species Litoria aurea, L. dentata and L. peronii

Exposure to increasing levels of ultraviolet-B (UV-B) radiation due to anthropogenic reduction of stratospheric ozone (03) has been suggested as a possible cause of amphibian population declines. Amphibians routinely bask in sunlight as a means of raising their body temperature to levels at which they can assimilate their food more effectively, but unless they are able to detect and behaviourally avoid high-level UV-B radiation, they risk sustaining UV-B-induced DNA damage if basking occurs when 03 levels are low. It is possible that a differential ability to detect and avoid UV-B radiation may be responsible for differences in the population stability of some amphibian species. When placed in an artificial environment which allowed a choice between high-level UV-B radiation versus UV-B-free conditions, larval L. aurea and L. peronii were observed more frequently in the UV-B-free environment (p = 0.004 and 0.04), while tadpoles of L dentata and adult L. aurea and L. peronii showed no significant preference. There were no significant differences between species in the proportion of times they were observed under the UV-B-blocking filters. These results suggest that differences in population stability between these species are unlikely to be due to a differential ability to detect and respond to peaks in UV-B radiation.