Scientists uncover parental behavior of glassfrogs

March 31 (UPI) -- Researchers at the Smithsonian Tropical Research Institute documented previously unknown parental-care behavior of translucent glassfrogs in a recent study.

"These are relatively well-studied, charismatic frogs, yet we were fundamentally wrong about their reproductive behavior," Karen Warkentin, an associate scientist at the Smithsonian Tropical Research Institute and professor at Boston University, said in a press release.

Glassfrogs mate during the night and laying their eggs from leaves that hang over running water.

Researchers observed the glassfrogs overnight and found female frogs will sit on their eggs for up to five hours after laying them. The frogs' translucent bellies absorb water from leaves to hydrate the jelly-coated eggs, causing them to swell up to four times its thickness to protect the developing embryos from predators and fungal infections.

Previous research showed only males of certain glassfrog species laid on eggs but the new study shows that every species they observed cared for their eggs.

Researchers observed 13 species from egg laying to tadpole hatching for parental behavior for six rainy seasons at 22 streamside locations in Mexico, Panama, Colombia, Ecuador and Peru, and found that fathers cared for the eggs much longer than mothers, through to tadpole hatching.

They theorized that first-night brooding was mostly done by mothers as an ancestral trait but over time more of the brooding was done by the fathers.

"It seems that fathers not only took over the job when mothers were already doing it, but they also greatly elaborated the amount of care," said Karen Warkentin, an associate scientist at the Smithsonian.

Researchers also conducted experiments in Panama on two species of glassfrogs and found brooding greatly increases the embryos' chances of survival.

The study was published in the Journal of Evolutionary Biology