The “blue-jeans” poison dart frog, also known as the strawberry poison dart frog, is small in size but serves an important role in La Selva Biological Reserve in Sarapiquí, Costa Rica.
The frogs are easily recognizable with their bright red head and back and blue legs that make it look as if they are wearing jeans. Subpopulations have different color patterns.
While the blue-jeans is not known to be lethal to humans, there are over 100 species of poison dart frogs, some of which can kill a human.
The blue-jeans can grow up to an inch and feed primarily on ants and termites. Keeping insect populations under control is one of its main functions, but this tiny creature also acts as a health indicator for the forest it lives in.
Melanie Allen, a senior at the University of Delaware, is at the La Selva Biological Research Station with the Research Experience for Undergraduates (REU) program studying the blue-jeans and the effects of deforestation on the frogs.
“They are so sensitive to chemicals in the area, or even the smallest change in temperature, they act as really good health indicators for the forest,” she said. “You can tell the well-being of the forest just by studying these frogs.”
Allen’s experiments consist of capturing frogs and putting them in a pasture to simulate the effects of deforestation. So far Allen has caught 302 frogs.
“It takes about three hours just to find 10 frogs,” said Melissa Diaz, Allen’s assistant. “We wear gloves and catch them by hand. We should probably use nets because a lot of the time we’re sticking our hands in all kinds of growth or debris, and you never know what you’ll find in there.”
About 80 percent of the frogs tested are able to orient themselves in the direction of the nearest forest and begin to make the journey.
If the blue-jeans are not able to make it back to their natural, humid habitat they will die. While not on the endangered species list, the blue-jeans still faces problems with deforestation clearing large areas of their habitat.
“The change in humidity between the forest and the pasture is enough to kill them if they aren’t reintroduced to their natural habitat in a certain amount of time,” Allen said. “They need the humidity that the rain forest offers and the pasture doesn’t have the right kind of cover that they look for. But after we test them we recapture them and take them back to where they were found.”
With the loss of habitat also come new problems. Blue-jeans are very territorial, especially during mating season. (To hear the mating call of a blue-jeans, click here.)
“The males will wrestle each other for as long as it takes,” Diaz said. “They don’t stop until one is pinned and the winner lets the loser up.”
Despite the hardships these frogs face, they are thriving in La Selva. The red-and-blue frog has become one of the faces of the Costa Rican rain forests.
“Our research is really about bringing awareness to these frogs and the potential danger they face,” said Allen. “They’re small but they’re also very important to the forest.”
Click here to learn more about amphibian conservation in Costa Rica.
Photos by Matt Lechuga.