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http://www.denverpost.com/nationworld/ci_7114905

Worsening plight of the bumblebee worries scientists
By JEFF BARNARD Associated Press Writer
Article Last Updated: 10/08/2007 01:29:16 AM MDT

GRANTS PASS, Ore.—Looking high and low, Robbin Thorp can no longer find a
species of bumblebee that just five years ago was plentiful in northwestern
California and southwestern Oregon.

Thorp, an emeritus professor of entomology from the University of
California at Davis, found one solitary worker last year along a remote
mountain trail in the Siskiyou Mountains, but hasn't been able to locate
any this year.

He fears that the species—Franklin's bumblebee—has gone extinct before
anyone could even propose it for the endangered species list. To make
matters worse, two other bumblebee species—one on the East coast, one on
the West—have gone from common to rare.

Amid the uproar over global warming and mysterious disappearances of
honeybee colonies, concern over the plight of the lowly bumblebee has been
confined to scientists laboring in obscurity.

But if bumblebees were to disappear, farmers and entomologists warn, the
consequences would be huge, especially coming on top of the problems with
honeybees, which are active at different times and on different crop
species.

Bumblebees are responsible for pollinating an estimated 15 percent of all
the crops grown in the U.S., worth $3 billion, particularly those raised in
greenhouses. Those include tomatoes, peppers and strawberries.

Demand is growing as honeybees decline. In the wild, birds and bears depend
on bumblebees for berries and fruits.

There is no smoking gun yet, but a recent National Academy of Sciences
report on the status of pollinators around the world blames a combination
of habitat lost to housing developments and intensive agriculture,
pesticides, pollution and diseases spilling out of greenhouses using
commercial bumblebee hives.

"We have been naive," said Neal Williams, assistant professor of biology at
Bryn Mawr College in Pennsylvania. "We haven't been diligent the way we
need to be."

The threat has bumblebee advocates lobbying Congress to allocate more money
for research and to create incentives for farmers to leave uncultivated
land for habitat. They also want farmers to grow more flowering plants that
native bees feed on.

"We are smart enough to deal with this," said Laurie Adams, executive
director of the Pollinator Partnership. "There is hope."

Companies in Europe, Israel and Canada adapted bumblebees to commercial use
in the early 1990s, and they are now standard in greenhouses raising
tomatoes and peppers.

Demand is growing as supplies of honeybees decline, especially for field
crops such as blueberries, cranberries, watermelon, squash, and
raspberries, said Holly Burroughs, general manager for production for the
U.S. branch of Koppert Biological Systems Inc., a Netherlands company that
sells most of the commercial bumblebees in the U.S.

One new customer is Tony Davis of Quail Run Farm in Grants Pass. He has
long depended on volunteer bumblebees to fertilize the squash, cucumbers,
tomatoes and eggplant he grows outdoors for sale in growers' markets. When
he started growing strawberries in greenhouses this year to get a jump on
the competition, he bought commercial bumblebee hives to fertilize them.

"Without bumblebees, I would be out of business. I don't think I could
hand-pollinate all these plants," he said.

Scientists hoping to pinpoint the cause of the nation's honeybee decline
recently identified a previously unknown virus, but stress that parasitic
mites, pesticides and poor nutrition all remain suspects.

Unlike honeybees, which came to North America with the European colonists
of the 17th century, bumblebees are natives. They collect pollen and nectar
to feed to their young, but make very little honey.

A huge problem facing scientists is how "appallingly little we know about
our pollinating resources," said University of Illinois entomology Prof.
May Berenbaum, who headed the National Academy of Sciences report.

Scott Black, executive director of the Xerces Society for Invertebrate
Conservation in Portland, worries that on top of pesticides and narrowing
habitats, disease could be the last straw for many of the bee species.

"It definitely could all come crashing down," he said.

More on bumblebees: http://www.bumblebee.org