The survival of a spectacular American species depends this week on a small band of volunteers wandering in the dense tropical hardwood hammock of the Florida Keys. Despite the heat and humidity, the searchers must wear heavy jackets, gloves, face masks, and other protective gear to keep off the swarming mosquitoes. It’s backcountry work, often knee-deep in the water, constantly scanning for Schaus’s swallowtail butterfly, a beautifully colored creature with a wingspan as big as a man’s hand, and which is now on the brink of extinction.
Since the emergency collecting effort began back in April, the searchers have found just a single adult, a female. They netted her two weeks ago on Elliott Key in Biscayne National Park and kept her there for four days in a special container, hoping she would produce a crop of up to 400 eggs. But rainy weather worked against them, and she yielded only a single egg before being released.
The researchers have also collected six Schaus’s larvae, and they were of different ages, suggesting they came from multiple females. “So we’ve captured a good bit of genetic diversity,” said University of Florida entomologist Jaret C. Daniels. There’s also still a chance they will get more. But with a tropical depression looming on the Gulf Coast and just a week till the end of the breeding season, he’s not optimistic.
The fate of the species may thus depend on those seven specimens, each now being kept in a separate plastic cup in Daniels’ lab in Gainesville. Assuming they yield a few adult females, those seven may just be enough to reintroduce this critically endangerd species to the wild. The University of Florida has done it once before, beginning in 1992 when the U.S. Fish and Wildlife Service authorized the first captive-breeding program. The timing then was perfect: Researchers collected eggs and larvae during the breeding season, just before Hurricane Andrew wiped out wild populations of the species that August. The program eventually bred up and reintroduced thousands of Schaus’s swallowtails, before federal officials decided in 2008 to shift their limited funding to other species.
But according to Daniels, a prolonged drought, together with loss of habitat to development, insecticide spraying for mosquitoes in populated areas, and possibly some other factor not yet known, have again conspired to deplete the population. “It’s the tenuous nature of conservation. Victories are often small, and they may not last as long as you hope.” Searchers last year found only four Schaus’s swallowtails, leading to a federal emergency order for this year’s collection to renew the captive-breeding program.
Daniels is careful to credit his partners in the current effort, including the North American Butterfly Association and various state and federal agencies. But for Thomas Emmel, a retired University of Florida professor who organized the earlier captive-breeding program, the federal decision to let it lapse still rankles. “It’s frustrating to have your hands tied,” he told the Tampa Bay Times last year, “by bureaucratic indecision that lets things drift so far downward.”
Schaus’s swallowtails produce only a single generation each year, according to Daniels. Even so, he said, the new program could begin to return butterflies to the wild within two years. The National Park Service has also begun to plant hundreds of torchwood trees, the preferred host plant for the species, to expand the available habitat. But whether the Schaus’s swallowtail will ever flutter through that forest again now seems to hang on those seven plastic cups in Gainesville.