http://www.bloomberg.com/apps/news?pid=20601124&sid=aTRSdWWGdLOE&refer=home
Bee Disease Spread From Commercial Hives, Study Finds By Alan Bjerga
July 23 (Bloomberg) -- Wild bumblebees are probably contracting a disorienting and often fatal
disease from their commercial cousins, contributing to the decline of pollinators in North America,
a Canadian study concludes.
Managed bumblebees, which pollinate crops worth about $19 billion worldwide, are introducing
illnesses that have ravaged wild populations of the same species, according to the study, which is
being published online today in the science journal PLoS One. Feral bee losses also harm
commercial hives, which are built partly by collecting from the wild.
Bumblebees are the second-biggest pollinating insect in the U.S. after honeybees, which are
threatened by Colony Collapse Disorder, a separate ailment marked by the sudden, massive
disappearance of bees that occurred in at least 35 states and three continents last year. The
study's findings point to a need for commercial beehives of all species to be managed more
effectively, said co-author Michael Otterstatter of the University of Toronto.
``Improved management of domestic bees is seemingly exactly what is needed -- greater
attention to the types of parasites they have,'' said Otterstatter, who conducted his research with
University of Toronto colleague James Thomson.
Potentially `Devastating'
``Pathogen spillover, whether it's in bumblebees or in something like Colony Collapse Disorder,
has the potential to be just devastating for the wild bee communities.''
In the study, the researchers examined bees at four Ontario sites near commercial greenhouses to
see whether a parasite common in managed bumblebees was unusually prevalent in the wild
population. The parasite robs bees of their ability to distinguish between flowers that contain
nectar and those that don't, Otterstatter said. For commercial bees fed by their owners, that skill
isn't important. For wild bees, its absence is deadly.
``Infected bees make an incredible number of mistakes,'' Otterstatter said. ``They visit empty
flowers again and again'' as they slowly starve to death, he said.
The study found that up to half the wild bees near greenhouses were infected with the pathogen,
while no bees were infected far from greenhouses. The research model predicts that, over time,
diseases transmitted from commercial bees will lead to widespread epidemics among wild bees.
Pollination
The finding is important because wild bees play a major role in pollinating crops ranging from
apples to zucchini, Otterstatter said. And because it's nearly impossible to keep commercial bees
of any species from mingling with feral cousins because of how they're used -- greenhouses have
vents, and honeybees are released in open fields -- proper care and feeding of commercial
beehives is essential, he said.
Otterstatter said he hopes his study on bumblebees will spur similar inquiries on the disease
relationship between wild and commercial honeybees. Scientists have gained little understanding
about why more than a third of U.S. honeybees died during the past two winters, a phenomenon
that may affect crop pollination next year, experts told a congressional committee last month.
U.S. Research
The University of Georgia received $4.1 million July 17 from the U.S. Department of Agriculture to
search for the cause of Colony Collapse Disorder and find ways to improve bee health.
``Bees are an extremely valuable contributor to the overall productivity of American agriculture,
but invasive pests, diseases and environmental stresses are putting U.S. bees at serious risk,''
Agriculture Secretary Ed Schafer said in a statement announcing the grant.
The University of Toronto bumblebee study was funded by the Natural Sciences and Engineering
Research Council of Canada and Ontario Graduate Scholarships.
Nationally, the commercial honeybee population dropped more than 36 percent this year,
according to a survey by the Apiary Inspectors of America. Commercial bees, which do most of the
pollinating for a third of U.S. crops, have declined during the past two decades to about 2.3
million honey-producing colonies from about 3.5 million.
Commercial bees add $15 billion annually in value to U.S. crops, according to the Agriculture
Department. Pesticides, mites and viruses are the leading suspects behind colony collapse. Wild
bees have a tougher time surviving than commercial bees, which are closely monitored,
Pennsylvania State University beekeeper Maryann Frazier said last month.
To contact the reporter on this story: Alan Bjerga in Washington at [log in to unmask]
Last Updated: July 23, 2008 11:56 EDT
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