Presentation Type

Poster

Presentation Type

Event

Keywords

Ultraviolet-B Radiation, Amphibians, Amphibian Skin Secretions, Frog Morphology, Southern California Frogs, UVBR

Department

Biology

Major

Biology

Abstract

As an increasing number of their species face possible extinction, amphibian populations have been steadily declining over the past decades (IUCN). While various factors have been suggested or proven to be partially responsible for this reduction, increased ultraviolet B radiation (UVBR) appears to be one of the more prominent explanations, especially when considering the continual thinning of the Earth’s ozone layer due to anthropogenic climate change. However, it has also been discovered that skin secretions, which are reported to function as a component of amphibians’ innate immune systems, may have an effect on UVBR (Cramp and Franklin). With this in mind, we wondered if the skin secretions of two local frog species, California tree frogs (Pseudacris cadaverina) and Pacific tree frogs (Pseudacris regilla), might be indicative of this. We hypothesized that a small glass slide consisting of an individual frog’s secretory layer would have a lower ultraviolet radiation reading than that of an unaltered glass slide, suggesting that a frog’s secretions protect it from a quantifiable amount of harmful UVBR. Using a consistently positioned UV meter, six frogs of each species were collected and tested independently at the streambank in Arroyo Sequit Park. Wavelengths of an individual’s secretions were recorded five separate times, with control measurements being taken before and after each trial. While nearly all secretions from both sampled species saw a slight decrease in UVBR levels when compared to the control readings, our findings were not significant enough to support our hypothesis, suggesting that amphibians’ skin secretions act as only a minimal deterrent to ultraviolet radiation.

Faculty Mentor

Dr. Lee B. Kats

Funding Source or Research Program

Academic Year Undergraduate Research Initiative

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Effectiveness of Frog Skin Secretions Against UV-B Radiation

As an increasing number of their species face possible extinction, amphibian populations have been steadily declining over the past decades (IUCN). While various factors have been suggested or proven to be partially responsible for this reduction, increased ultraviolet B radiation (UVBR) appears to be one of the more prominent explanations, especially when considering the continual thinning of the Earth’s ozone layer due to anthropogenic climate change. However, it has also been discovered that skin secretions, which are reported to function as a component of amphibians’ innate immune systems, may have an effect on UVBR (Cramp and Franklin). With this in mind, we wondered if the skin secretions of two local frog species, California tree frogs (Pseudacris cadaverina) and Pacific tree frogs (Pseudacris regilla), might be indicative of this. We hypothesized that a small glass slide consisting of an individual frog’s secretory layer would have a lower ultraviolet radiation reading than that of an unaltered glass slide, suggesting that a frog’s secretions protect it from a quantifiable amount of harmful UVBR. Using a consistently positioned UV meter, six frogs of each species were collected and tested independently at the streambank in Arroyo Sequit Park. Wavelengths of an individual’s secretions were recorded five separate times, with control measurements being taken before and after each trial. While nearly all secretions from both sampled species saw a slight decrease in UVBR levels when compared to the control readings, our findings were not significant enough to support our hypothesis, suggesting that amphibians’ skin secretions act as only a minimal deterrent to ultraviolet radiation.

 

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