How the Tree Frog Has Redefined Our View of Biology

The world’s most charismatic amphibian is upending the conventional wisdom about evolution

A beloved symbol of biodiversity, the red-eyed tree frog, shown here in Panama, has evolved a flexible strategy for survival. (Christian Ziegler)
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In a study published last month, he found that eggs were more likely to survive on land if there was a lot of rain, and more likely to survive in water if rainfall was scarce. He also looked at rain records for Gamboa in the past 39 years and found that while overall rainfall hasn’t changed, the pattern has: Storms are larger but more sporadic. That change in the environment could be driving a change in how the hourglass tree frogs reproduce. “It gives a window on what caused the movement to reproducing on land to occur,” Touchon says—a climate that shifted to have lots of steady rain could have made it safer for frogs to lay eggs out of the water.

Warkentin’s group is based on the ground floor of the Gamboa Elementary School, which closed in the 1980s. One morning, Warkentin sits on an ancient swivel chair with dusty arms at a retired office desk, doing what looks like a grade-school craft project.

On the floor at her left sits a white bucket with rows of green rectangles duct-taped to the inside. She reaches down and pulls one out. It’s a piece of leaf, cut with scissors from one of the broad-leafed plants by the experimental pond, and on it is a clutch of gelatinous red-eyed tree frog eggs. She tears off a strip of tape and sticks the piece of leaf onto a blue plastic rectangle, cut from a plastic picnic plate.

“You can do an amazing amount of science with disposable dishware, duct tape and galvanized wire,” she says.

She stands the card in a clear plastic cup with a bit of water in the bottom, where the tadpoles will fall when they hatch, and goes on to the next piece of leaf. The tadpoles will be part of new predation experiments.

There’s great explanatory value in simple models—but she wants to understand how nature actually operates. “We’re trying to grapple with what’s real,” she says. “And reality is more complicated.”


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