for National Geographic News
Sun-loving tree frogs from Costa Rica could get a reprieve from dissection—thanks to a tool borrowed from eye doctors.
The technique, called optical coherence tomography (OCT), can produce images to a depth of a few millimeters and is normally used to examine the human retina, a thin layer of cells that lines the back of the eyeball.
But animal conservationists in Manchester, England, are using OCT to study skin characteristics in frog species that bask in the sun—an unusual trait among thin-skinned amphibians.
The team hopes that the noninvasive method will yield clues about the frogs' susceptibility to a deadly chytrid fungal infection, a disease found worldwide that has been linked to global warming.
Andrew Gray is curator of herpetology at the Manchester Museum and a co-author of the new work, which also involves researchers at the Photon Science Institute at the University of Manchester.
So far Gray and his colleagues have been testing the OCT technique on the museum's extensive collection of rare Phyllomedusine and Litoria tree frogs.
The new method isn't ready for publication, the researchers say, but it has been unveiled at two in-house poster sessions.
"We currently know that a few specimens of frogs suffering from skin infections appear to become immune to chytrid after suffering [the disease] and then being cleared through treatment," Gray said.
"If this is due to skin structure change or difference, we hope the OCT equipment being developed will be able to let us see how—without dissecting the frogs."
The frogs at the heart of the Manchester study lead unusual lives in their wild treetop habitats—they often bask in the hot sun.
Frogs drink and breathe through their thin, permeable skin, so they normally avoid prolonged exposure to direct sunlight due to the risk of overheating and dehydration.
SOURCES AND RELATED WEB SITES