In the case of Hypsiboas punctatus, we found that under twilight-nocturnal conditions, between 18% and 30% of all the light…

In the case of Hypsiboas punctatus, we found that under twilight-nocturnal conditions, between 18% and 30% of all the light (photons) emanating from the frog’s skin were florescent. That’s a substantial proportion, enough to add significant fluorescence to the typical green (in daylight) colouration of the frog, enhancing its visibility.

Finding fluorescence in a land animal is particularly interesting because it has been generally considered irrelevant but for its presence in some insects (spiders, scorpions, beetles, butterflies, moths, dragonflies, millipedes) and in two avian species, parrots and parrotlets. In parrotlets, differences in feather fluorescence between sexes have been found to serve a function in mating and attraction.

With the polka-dot tree frog, we expect that its fluorescence plays a role in inter-species visual communication (because it matches the sensitivity of the frogs’ eyes photoreceptors for blue and green). We do not believe that it has any relevance to mating, as florescence does not seem to differ between females and males.

(via https://theconversation.com/the-worlds-first-glow-in-the-dark-frog-found-in-argentina-74602)