Tuesday, May 1, 2012


Urban Buzz: A New Bee That Sips Sweat Native Insects Getting Closer Look; Humans as 'Salt Lick' By ROBERT LEE HOTZ NEW YORK—A new bee is buzzing in Brooklyn: The tiny insect, the size of a sesame seed, sips the sweet nectar of the city—sweat. "They use humans as a salt lick," said entomologist John Ascher, who netted the first known specimen of the species in 2010 while strolling in Brooklyn's Prospect Park near his home. "They land on your arm and lap up the sweat." North America is home to thousands of species of native bees. But they have long been overshadowed by imported honeybees, prized for their honey and beeswax since the time of the Pharaohs and a mainstay of commercial agriculture. Now, native bees are generating serious buzz. New York City is a hive of activity and one of the most diverse cities in the world. It's also host to hundreds of bee species, including one newly discovered specimen that lives on human sweat. WSJ's Lee Hotz reports. For Mr. Ascher, 41 years old, nothing quite brightens the day like a new box of unidentified bees landing on his desk from some distant glade. So puzzling was the greenish-blue city bee he netted, though, that it took Mr. Ascher, who oversees a digital catalog of 700,000 bee specimens at the American Museum of Natural History, months to pinpoint its proper place in the insect kingdom. In the end, only DNA testing by sweat bee specialist Jason Gibbs at Cornell University could identify its niche. Last November, they announced the discovery of Lasioglossum gotham, in a peer-reviewed journal called Zootaxa. The newbie joined the growing catalog of easily overlooked wild native bees. Sweat bees don't have a high profile outside academic circles. Unlike honeybees, which were originally imported from Europe, native bees don't make much honey. To their credit, though, sweat bees rarely sting; their occasional pinprick registers a one on the Schmidt Sting Pain Index, the lowest on the four-point scale. (Bullet ants and the tarantula hawk wasp rate a four.) Photos: Sweat Bee Generates Buzz Jason Gibbs/Cornell University A new species of sweat bee, Lasioglossum gotham, was discovered in the Brooklyn borough of New York in 2010, joining the growing catalog of easily overlooked wild native bees. Shown, a Lasioglossum gotham specimen. More photos and interactive graphics These bees prefer sweaty people—over most animals—because the human diet usually is so salty that their perspiration is saturated with the essential nutrient, experts said. Yet most people never notice when the tiny bees alight on a bare arm or leg. As it turns out, Mr. Ascher and his colleagues are discovering New York City is a hive of activity. By latest count, about 250 species of native bees are known to nest in sidewalk cracks, traffic median strips, parks, and high-rise balcony flower pots—more perhaps than any other major city in the world, several entomologists said. In Prospect Park alone, at least 90 species of native bees flit from flower to flower among the park's sun-dappled golden rod, dandelions and dogwood. "For certain species, the city is as good as or better than a natural area," Mr. Ascher said. Hovering around city parks and flower beds are masked bees, miner bees, mason bees, plasterer bees, cuckoo bees, leafcutter bees, horned bees, and at least 49 species of sweat bees. "We routinely see bees 30 stories up in window gardens," Mr. Ascher said. A local bumblebee has even been spotted on the observation deck of the Empire State Building. Sweat bees often live unobtrusively. "You can have sweat bees nesting in your front yard and never know it," because they are so small and mild-mannered, said Cornell's Mr. Gibbs. "Hundreds can nest in a square meter of lawn." As an urban wilderness, New York City continues to surprise field biologists. Not so long ago, museum bug hunters discovered a new genus of centipedes—perhaps the world's smallest—under the fallen leaves in Central Park. In 2009, a new species of cockroach turned up in a West Side supermarket. Earlier this year, researchers at Rutgers University and the University of California identified a previously unknown species of leopard frog whose natural range centers on Yankee Stadium. The discovery of this new sweat bee species—which belongs to a large family of bee species that depend on human perspiration for salt to survive—highlights the importance of the thousands of native bee species in pollinating plants, flowers and fruits. Sweat bees aren't ready to swarm into the commercial workplace. But other native bees are gaining scientific attention at a time when honeybee hives are plagued by myriad problems that threaten their survival. Sweat Bee "We've neglected the native bees because the honey bee was so successful," said entomologist Anne Averill at the University of Massachusetts in Amherst who is conducting a $3.3 million federal study of native bees in 10 states. They hope to expand the role of native bees in agriculture. Not a single native plant in North or South America actually needs a honeybee to survive, so long as native bees thrive, museum and university entomologists said. Untended and largely unnoticed, native bees play a role in pollinating cash crops such as tomatoes, cranberries, alfalfa and squash. They are more prevalent among farmers' fields than previously believed, often more effective than honeybees as pollinators and more resistant to the problems that have decimated honeybees in the U.S. and Europe, several studies show. Unlike many honeybees, urban bees in the Northeastern U.S. have adapted to rising temperatures, which have caused spring—and the first bloom of flowers for pollination—to arrive about 10 days earlier in recent years, Rutgers University researchers said. It isn't easy keeping track of so many bees. Sweat bees encompass an unusually broad range of behaviors, but often differ from each other in almost imperceptible ways. All that distinguishes the Gotham sweat bee from its most closely related species is the pattern of bristles on its abdomen and a few links of DNA. They are so hard to tell apart that agriculture experts world-wide are hard-pressed to take stock of them all. "If there is a new bee species in New York, imagine the situation...somewhere in South America," said Mr. Ascher. "It is hard to effectively manage pollinators if they have not been named scientifically." At the American Museum of Natural History, Mr. Ascher and his colleagues scramble to keep up with requests to catalog unidentified bee species. Museum corridors are a honeycomb of bee boxes and specimen drawers packed with 450,000 preserved bees. Almost every day new native bee specimens arrive in the mail. "We are finding out these things at a fast pace," Mr. Ascher said. "I just got another box of bees and there was a new species in Queens." Write to Robert Lee Hotz at sciencejournal@wsj.com