Support for Dean's argument:

Penn State researchers are making progress in pinning down the cause
or causes of Colony Collapse Disorder (CCD), a mysterious ailment that
threatens the beekeeping industry and the crops and native plants that
rely on honey bees for pollination.

In fall 2007, a team led by Diana Cox-Foster, professor of entomology,
reported a strong correlation between CCD and the presence of Israeli
acute paralysis virus, making the pathogen a prime suspect in the
disease. Since that time, researchers have introduced IAPV to healthy
honey bee colonies in a controlled greenhouse environment in an effort
to induce a collapse.

"Within one week of introducing the virus, we observed dramatic bee
mortality, with bees dying outside the colonies across the room in the
greenhouse," said Cox-Foster. "Bees were found on the floor with
paralytic-type movements, and guard bees were observed removing
paralytic bees from colonies and flying across the room. The majority
of these 'twitcher' bees were found to have IAPV."

Cox-Foster noted that within a month, infected colonies had declined
to small clusters of bees, many of which had lost their queens. "These
data indicate that IAPV is a highly pathogenic virus," she said. "But
they do not yet support a finding of IAPV as the sole cause of Colony
Collapse Disorder. We still suspect that additional stresses are
needed to trigger CCD."

Among the potential triggers being investigated are environmental
chemicals. Penn State scientists analyzing pollen, wax, adult bees and
brood (larvae) have found the presence of dozens of chemicals,
including pesticides used by agricultural producers to protect crops
and by beekeepers to control hive pests such as parasitic mites.

"This raises several complicated questions," said Maryann Frazier,
senior extension associate in entomology. "Some of these compounds
could react with each other to cause toxic effects or could combine
with viruses or poor nutrition to weaken immunity and cause colony
collapse. We also need to do more research to understand these
chemicals' sub-lethal effects on bees."

Though the role of chemicals in Colony Collapse Disorder is still
unknown, Frazier noted that beekeepers need more options for
controlling varroa mites so they can reduce their reliance on
chemicals. "With the sheer number of compounds we're finding in hives,
it's hard to believe that pesticides aren't contributing to the
general decline in bee health," she said.

-- 
Peter L Borst
Danby, NY USA
42.35, -76.50
http://picasaweb.google.com/peterlborst

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