Scientists revealed a natural marvel in 2017. Scientists discovered that some frogs glow in the twilight with a fluorescent substance. Nature has a lot of surprises for us..
The number of species that emit fluorescence was not known at the time. New research has undertaken to find out – and it’s many, many more than This initial discoveryHinted at.
In a study of 151 species of South American frogs, every single individual – that’s 528 frogs – exhibited some degree of fluorescence.
Moreover, the research – Published at the preprint server BioRxiv – suggests that fluorescence is well matched to frogs’ vision and ecology, indicating it plays a role in the way the frogs signal to each other, and maybe to ward off predators.
In a field study across South America we documented biofluorescence patterns in tropical amphibians. We tripled the number species that were tested and included representatives of previously untested families. Courtney Whitcher leads a team of biologists to write a series of articlesFlorida State University
Our results indicate that frog biofluorescence may be used in anuran communication.
It’s not always easy to tell why animals glow.
It is caused by light being absorbed then re-emitted in a different frequency. Catharks, Chameleons, SalamandersAustralians have a peculiar way of speaking monotremesThe following are some examples of how to get started: Marmosets. Bones also fluoresce; yes, even yours.
However, the biofluorescence that frogs produce in their skin is different from other glowing animals. Whitcher and her research team captured and studied 528 South American frogs, using lights from the ultraviolet to visible spectrum.
The study found that every frog returned a glow, even though the amount of return glow varied from 2 to 10 percent. The ‘how” of the glow may be more interesting than its existence.
The strongest fluorescence was seen in the blue wavelength closest to Earth’s natural sunset. And the fluorescence itself occurred primarily in two different visible-light peaks – one green, and one orange.
Many frogs have crepuscular behavior, which means they are most active during the dark hours of dawn or dusk. In some species, their eyes are structured to work best in this light, dominated by rod photoreceptors sensitive to green and blue – green in particular. Green-sensitive rods account for 60 percent or more of the retinal space of some species of frogs, according to the researchers.
It means that the green glow of their eyes is most intense during the times when the frogs have been the busiest. The parts of the frog’s body that glow most are those involved in communicating with other frogs. This includes the throat and back. This indicates that biofluorescence may be a part of the frogs communication toolkit.
What about the orange-colored fluorescence though? This could be an evolution byproduct from the biofluorescence of frogs. It could also be a warning signal for a predator to stay away. The orange glow will require more research to discover what it means.
According to the researchers, the green glow does meet all the criteria needed to prove its significance.
The biofluorescence of many frog species is similar to the peak perception of anuran rods, but it differs greatly from background colors that are reflected at normal breeding hours for frogs. This makes biofluorescence more visible during these hours.” They write on their paper.
The results of our research suggest that the evolution and function of biofluorescence may be influenced by sensory drive. This will inspire future studies on its role in communication between anuran species.
The study is available at BioRxiv.
