Sunlight has two different types of ultraviolet rays, UV-A and UV-B. It isn’t a surprise that ultraviolet rays (in large amounts) harm not only humans, but also a tiny frog found in the Neotropics. Scientists at La Selva Biological Station in Costa Rica have researched the strawberry dart frog, Oophaga pumilio, and the influence UV levels have on this tiny strawberry colored frog.
The authors observed two things with male adult frogs, UV-B & perch height and UV-B & perch time. Their methods were to measure frogs’ perch height, air temperature, the UV levels at the perch site, visible light, and call duration. After observing 69 adults, they found that their results supported their hypothesis: UV-B did influence perch selection.
Adult male frogs would select perches with lower UV-B levels when calling for mates, although it was revealed that when researchers would artificially increase visible light levels, a frog would stay on longer. Other research suggests that female dart frogs use visual indicators to aid in selecting a mate.
Why are these findings important? The strawberry dart frog is a secondary consumer and preys upon insects, eggs, spiders, and ants. This frog may be tiny and poisonous, but it is part of a food chain. They also are found in humid forests.
Kats, L., Bucciarelli, G., Schlais, D., Blaustein, A., Han, B., & Navas, C. (2012). Ultraviolet Radiation Influences Perch Selection by a Neotropical Poison-Dart Frog. PLOS ONE 7(12), E51364.