Nicole Povelikin: Fluorescent Frog Ecology

Perplexed by the bizarre diversity of reptiles and amphibians, I seek to understand the
evolutionary and ecological mechanisms through which morphological, species, and genetic diversity arise. Growing up in the heart of New York City, where herpetological diversity is mostly limited to people’s released pet turtles, I always hoped to one day escape the city to a more biodiverse and herpetologically rich ecosystem. The swampy landscape just outside of FSU has been incredibly intellectually stimulating to explore as a biology major and Presidential Scholar over the past two years, but much of evolutionary biology relies on comparative methodology and I have little to compare the swamps of Florida to.

Nicole Povelikin, Junior, Biological Science 

I attempted to embark on research in neotropical herpetology last summer, but accidentally ended up in the desert landscape of the North American Southwest instead. I enjoyed learning about arid land ecology and the remarkable adaptations of desert herps, but remained curious about neotropical herpetofauna. I intend to begin graduate school after graduating from FSU, and eventually pursue a career in evolutionary and herpetological research. I am thus incredibly excited to spend this summer in a tropical ecosystem investigating the ecological correlates of frog biofluorescence.

Biofluorescence, the absorption of light and re-emission at longer wavelengths, was first discovered in an amphibian in 2017. Since then, biofluorescence has been documented in additional species and researchers have begun investigating the function, evolution, and mechanisms behind amphibian biofluorescence.

Intriguingly, past research has found a correspondence between the spectral sensitivity and the fluorescent emission spectra in tree frogs, suggesting it is possible that tree frogs use fluorescent emissions to communicate. Whether biofluorescence functions as a visual intraspecific signal or not, ecological selection pressures might have shaped the diversification of biofluorescent patterns in amphibians. Amphibian biofluorescence could serve as aposematic warning signals or mimetic signals directed at predators, for example. Like color which serves diverse functions including sexual signaling, thermoregulation, camouflage and mimicry, the evolution of diverse biofluorescent patterns probably cannot be attributed to a single evolutionary function. Nevertheless, communication likely plays some role in the evolution of biofluorescence.

Biofluorescent Frogs, courtesy of Save the Frogs

If fluorescent signals are for communication, I hypothesize that species in similar microhabitats will converge on similar patterns of biofluorescence because of similar selective pressures influencing the transmission of signals. This would concord with a hypothesis of sensory drive, positing that both signals and signal receiving mechanisms are under different abiotic and biotic selective forces in diverse ecological environments to maximize the transmission of information and minimize the interception of signals by unintended receivers (e.g., predators).

In order to begin untangling the function and evolution of frog biofluorescence, I will travel to Yasuní National Park in Ecuador in May with graduate student Courtney Whitcher and Drs. Emily and Alan Lemmon. We will spend the month looking for a diverse set of frog species in one of the most biodiverse ecosystems on the planet.

We will collect all amphibians on nightly surveys, and I will record ecological data including the distance from ground, substrate, humidity, and temperature. Amphibians will then be brought back to the field station, where Courtney and I will use five different lights across a ~200 nm wavelength range to excite biofluorescence. We will photograph frogs and use a UV-VIS portable spectrometer to measure emissions wavelengths and intensity. Upon return home, images will be analyzed in ImageJ, which will allow me to extract categorical data on position of biofluorescent markings and quantitative data on the area of biofluorescent patches.

In preparation for field work, I have spent the past month assembling field gear, obtaining legal documents, and getting travel vaccines. I cannot wait to head out to Ecuador and begin data collection!

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