The Buzz at OSU By Denise Ellsworth 4/15/14
Across North America and beyond, bumblebees are in trouble, but gardeners can help these critical pollinators.
TO BIOLOGIST SAM DROEGE, they are “the teddy bears of the bee world.” Fat, fuzzy and occasionally clumsy fliers, “bumblebees are cute,” says Droege, who heads the U.S. Geological Survey’s Bee Inventory and Monitoring Lab. “People project emotions on them”—an assertion backed by the many children’s books and songs featuring bumblebees.
All members of the genus Bombus, the world’s roughly 250 bumblebee species are critical pollinators. In natural ecosystems, bees are by far the most important pollinators of native plants, and the insects are essential to producing more than a third of the foods and beverages humans consume—an industry worth hundreds of billions of dollars annually. Bumblebees are particularly major players: Because their large bodies allow them to generate heat, the insects can fly earlier and later in the day and in colder weather than most bee species, including honeybees.
Bumblebees are also strong flyers. Powered by contractions of the thorax, or midsection, the insects’ wings beat 130 or more times per second. That prowess, combined with their size, allows bumblebees to perform a unique service, “buzz pollination” (vibrating flowers until they release pollen), that helps plants produce more fruit. And bumblebees’ significance as pollinators has been growing in recent years as managed colonies of European honeybees decline.
But it turns out that bumblebees are in trouble, too. In North America, four once-common, widespread Bombus species have vanishedfrom large portions of their former ranges. A fifth may already be extinct...