Disease dooming native bumblebees

They work in the cold when honeybees are still snug in their hives, and cloudy days don't stop them either.

Bumblebees are workhorse pollinators, depended on to pollinate everything from cranberries and blueberries to hothouse tomatoes.

But native bumblebees are in trouble, victims of diseases some scientists say are spread by commercial bumblebees shipped around North America to pollinate crops.

While much attention has been given to the plight of European honeybees, dying in droves in so-called colony collapse disorder, the sharp decline of some species of native bumblebees has been largely overlooked.

The Xerces Society, based in Portland, several other environment groups and prominent entomologists joined together this week in supporting a citizen petition asking the U.S. Department of Agriculture to regulate the commercial bumblebee industry.

The petition asks the department to ban shipments of bumblebees outside their native range, and to require that bumblebees shipped within their native habitat be certified as disease free.

Scott Hoffman Black, executive director of the Xerces Society, said the rules are needed to prevent further decline of native bumblebees already in deep trouble, including the western bumblebee, the fuzzy bee of every Northwest kid's summer.

"The western bumblebee was one of the most common. If you lived in Seattle, Olympia, Vancouver, this is a bumblebee you would see in forest edges, clearings, yards," Black said. "Today it is gone from pretty much the entire Puget Sound area, as well as east of the Cascades."

He partly blames the escape of East Coast bumblebees, buzzing out of the vents of commercial greenhouses around the country where the bees have been shipped to pollinate crops.

They can carry diseases to which native bees — there are about 30 species on the Pacific Coast — have no resistance.

The Department of Agriculture had no immediate comment on the proposal, said Larry Hawkins, a spokesman for the agency.

States take a varied approach to bumblebee regulation. Oregon bans all importation of commercial bumblebees to protect native stocks, said Dan Hilburn, administrator of the plant division for the Oregon Department of Agriculture. Washington doesn't regulate bumblebee shipments at all.

Rene Ruiter, general manager for Koppert Biological Systems in Romulus, Mich., one of two companies commercially growing and shipping bumblebees in North America, said his company already has to certify its bees as disease free for its exports to Canada and Mexico.

Doing so for domestic shipments might not be a burden, depending on how a rule was written, he said.

In business since 1994, his company serves growers using bumblebees to pollinate greenhouse tomatoes, including about 800 acres in the United States. Only bumblebees can execute the deft maneuver required to pollinate a hothouse tomato, vibrating their entire fuzzy body to shake pollen loose.

But under regulations requested in the petition, the company's shipments of Bombus impatiens, a bumblebee native of the Eastern United States, would be shut down to the West.

"That's life," Ruiter said, "but we disagree with it. Our bees are already certified disease free for export and it's not as if we have one bee for export and another for shipping in the U.S."

He bristled at a study published in 2008 documenting much higher disease rates among wild bees collected close to greenhouses in Canada. "Those weren't our bees," he said.

Michael Otterstatter, a research biologist who did the work for the paper while at the University of Toronto, said the results of the study alarmed him.

The levels of disease around the greenhouses was much greater than he found in wild populations.

"It was a nasty shock," Otterstatter said. "I was holding on to the idea that even if the commercial bees are sick, they were isolated enough that they would not be having an effect on the native pollinators. But that turned out not to be the case."

Lynda V. Mapes: 206-464-2736 or lmapes@seattletimes.com