A Hawaii scientist has found a fly species whose bulging middle legs bear a resemblance to the spinach-fueled forearms of the cartoon sailor Popeye.
Campsicnemus popeye is one of six species with swollen legs found by Bishop Museum entomologist Neal Evenhuis.
Evenhuis, who found the Campsicnemus popeye in French Polynesia earlier this year, details the find and others in the current issue of the zoological journal Zootaxa. The discoveries were made in remote tropical island areas in Tahiti and the Marquesas, where Evenhuis began collecting flies along the banks of streams in 2006.
Evenhuis has been studying the long-legged flies of the genus Campsicnemus in both Hawaii and French Polynesia for almost 20 years. This group of flies occurs worldwide with a total of a little more than 300 species.
"Finding a huge diversity of species … is heartening," especially in light of many species facing extinction elsewhere in the world, Evenhuis said. There are nearly 100 species of the flies in Hawaii, and diversity appears to be also flourishing in high-elevation tropical islands in French Polynesia.
Despite its new name, Campsicnemus popeye, about a quarter-inch wide and long, is no spinach-eater. It’s a carnivore, feeding on other flies and maggots. It snares prey with its teeth and a syringelike tube.
The popeye fly has six legs and, like all flies, two wings.
Evenhuis said the swollen middle legs are an attribute that only the males have, apparently to excite and attract females of their species.
He said one of the six recent species was found in the Marquesas and the other five in the Society Islands.
Bishop Museum officials said that, over the years, the entomologist’s work has led to the discovery of 31 species in the genus Campsicnemus, with two dozen more awaiting review.
Evenhuis said the centers of diversity seem to be places that have small ravines or "niches," with ample rainfall. "It sometimes takes a helicopter to get to the best places," he said.
Land masses such as Tahiti and Maui are relatively young, about 2 million years old, with elevated rainfall peaks, where new species have an opportunity to flourish. "It’s a living laboratory of evolution," Evenhuis said. "We’re finding all kinds of things."
Flies are scavengers and pollinators, with both good and bad points. For example, Evenhuis said, "We wouldn’t have chocolate without flies because flies pollinate the cocoa plant."
Evenhuis said he hopes to find funding for further research hot spots of biodiversity in French Polynesia and Hawaii.
"I think the big question is, Why are there so many species?" Evenhuis said. "We may be on the brink of another frontier to see how things evolve."
