It was around 4 a.m. And for Jesse Delia, a graduate student conducting fieldwork in Panama, it had been a long night. His project wasn’t going well, and he was ready to head home. On his way back from the stream where he had been working, he stopped by a spot to have another look at a mating pair of frogs he had seen earlier. It didn’t relate to his project, but he wanted to see what they were up to.
There, a female glass frog was sitting on her eggs. He tried to nudge her off, but she wouldn’t budge. This was unusual. The books said most glass frog larvae were on their own after fertilization. And for the rare cases in which larvae did receive parental care, it came from the father.
Was this for real?
After that night, Mr. Delia set aside his original project and embarked on a five-year quest with Laura Bravo Valencia, a graduate student at the Universidad de los Andes in Bogotá, Colombia.
Together, they spent rainy all-nighters along wet streams at 22 research sites across Colombia, Peru, Panama, Mexico and Ecuador to see if this parental behavior could be found elsewhere and, if so, how it evolved.
In a paper published Friday in the Journal of Evolutionary Biology, they reported finding that what was once thought about glass frogs was wrong. It turns out that possibly all glass frogs provide some form of parental care; whether it’s the male or female depends on the species. Male parenting most likely evolved from a female caring ancestor multiple times within the glass frog family history, and the type of care then became more elaborate.
The results of their research were also a reminder that fieldwork remains a valuable tool for discovery in an era of indoor genetic labs.
“We were completely wrong about what we thought was going on in this group, and by accident, by staying out…