Volume 13, Number 1, 2004
When Justin Yeager, AG '05, had the opportunity to pursue his lifelong interest in frogs by participating in a study-abroad program in Costa Rica last year, he jumped at the chance. But, he says, he had no idea the program would develop into the kind of experience for which a scientist can wait a lifetime.
Yeager rediscovered the colorful harlequin frog (Atelopus varius), an amphibian species that had been thought to be extinct in the tropical rainforest of Costa Rica. The tiny frog--most are 1-1.5 inches long--had not been seen anywhere in that country since 1996.
"Atelopus varius was common to the Costa Rican rainforest until a decade ago, when a fungus resulted in their decline," Yeager says, adding that more than 50 percent of all dart frog species have become extinct.
The rediscovery of the harlequin was a happy accident, Yeager says. He had traveled to Latin America to study poisonous dart frogs and general herpetology at the University of Costa Rica. While there, he interacted with residents of the area, practicing his Spanish and teaching husbandry.
He says a local guide first told him about an unusually colorful and poisonous amphibian the man had seen living in the rainforest nearby. As Yeager listened to the description of what sounded like a harlequin, he says he was wary.
"I kept thinking that he had to be mistaken," Yeager says. "I knew that the species the man was describing was listed as extinct."
Despite his skepticism, he says his excitement grew, and he asked to see the frog. Because red tape prohibited Yeager from taking an immediate hike deep into the private rainforest reserve, the guide returned two days later with a harlequin pair.
Yeager says he knew immediately what he was seeing: The frogs with the black-and-neon-orange markings had not disappeared completely after all. "It's literally a second chance for this species," he says.
Yeager contacted Federico Bolaños, a herpetologist at the University of Costa Rica, who asked the student to bring in the frogs for positive identification and documentation. A DNA sample from the tiny amphibian's toe verified Yeager's on-the-scene identification, confirming the harlequin's continued existence.
Yeager then placed a call to the Atlanta Botanical Garden in Georgia, where an orchid garden had just opened. He says he knew that the tropical ecosystem of this garden was the ideal breeding place for harlequins in captivity, and he hoped to interest the scientists there in the discovery. He notes that the future of the species is not assured.
Of his own role in the discovery, he says, "I was in the right place at the right time."
Yeager's frog fascination began at age 5 when he visited the National Aquarium in Baltimore. "I was mesmerized by the brightly colored dart frogs," he says. "My parents had to pry me away from the display."
At age 9, he purchased his first dart frog. He added to his collection over the years, breeding and selling the frogs, until his bedroom in Ephrata, Pa., was taken over with terrariums containing hundreds of these amphibians. Yeager was forced to move his sleeping quarters to the basement of the house.
The amateur herpetologist entered UD as a business major, but he says he could not give up his interest in amphibians. He assisted with research in the laboratory of Doug Tallamy, chairperson of the College of Agriculture and Natural Resources' Department of Entomology and Wildlife Ecology. Yeager's continued fascination with the interaction and interdependence among dart frogs and other creatures eventually led him to change his major to wildlife conservation.
"Justin is the ideal student," Tallamy says. "He's so easy to teach. You just point him in the direction, and he teaches himself."
Yeager says he holds out great hope for the future of the harlequin. Many questions remain about the rare species, he says, and further research is under way. The Atlanta Botanical Garden has sent several groups of scientists to Costa Rica to try to determine how many of the frogs exist, why they have survived despite the fungus and whether it is feasible to breed them in captivity.
Ron Gagliardo, curator of tropical collections at the botanical garden, says Atelopus is known as an indicator species because of its susceptibility to the forces that lead to amphibian decline.
"There is no doubt this is an important discovery," he says of Yeager's sighting. "You could say that the Atelopus has become the poster child of global amphibian species decline."
Although Yeager says he would like to be working with harlequins, his immediate goal is to finish his education. After he graduates in May, he plans to pursue a doctorate and eventually teach, while continuing his rainforest amphibian research.
Additional photos of harlequins are available on his web site, [www.yeagersfrogs.com], by clicking on "Atelopus gallery."