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GreenWeek
ClickGreen’s review of all the week’s news, views, research and analysis with a focus on low carbon and sustainability
Volume 27: May 9, 2014
Bee decline study puts pressure
on UK to ban garden chemicals
Pressure on Government to acknowledge link between pesticides and bee deaths
By Stuart Qualtrough
T he UK Government’s to
refusal to ban chemicals
protect declining numbers
of bees has been questioned
after a new study by the Harvard
School of Public Health found
two widely used neonicotinoids
– a class of insecticide – appear
to significantly harm honey
bee colonies.
The study replicated a 2012
finding from the same research
group that found a link between low
doses of imidacloprid and Colony
Collapse Disorder (CCD), in which
bees abandon their hives over the
winter and eventually die. The new
study also found that low doses of a
second neonicotinoid, clothianidin,
had the same negative effect.
Although other studies have
suggested that CCD-related
mortality in honey bee colonies may
come from bees’ reduced resistance
to mites or parasites as a result of
exposure to pesticides, the new
study found that bees in the hives
exhibiting CCD had almost identical
levels of pathogen infestation as a
group of control hives, most of
which survived the winter.
This finding suggests that the
neonicotinoids are causing some
other kind of biological mechanism
in bees that in turn leads to CCD.
“We demonstrated again in this
study that neonicotinoids are
highly likely to be responsible for
triggering CCD in honey bee hives
Research undermines Government’s refusal to accept the scientific evidence
that were healthy prior to the
arrival of winter,” said lead author
Chensheng (Alex) Lu, associate
professor of environmental
exposure biology at HSPH.
The UK Government last year
said it did not accept the science
and refused to ban the chemicals
for parks and gardens, a position
supported by the National
Farmers Union.
The Government stated it was
not convinced by the results of
laboratory studies showing
harmful effects to bees and
argued that an “increasing
number of field-realistic studies
have failed to find an effect of
neonicotinoids on bees”.
Since 2006, there have been
significant losses of honey bees
from CCD. Pinpointing the cause is
The Government’s
draft plan is
dangerously
complacent on
pesticides, placing
far too much trust
in chemical firms and
flawed procedures
Paul de Zylva, Senior
Nature Campaigner,
Friends of the Earth
crucial to mitigating this problem.
Bees are prime pollinators of about
one-third of all crops worldwide.
Experts have considered a
number of possible causes,
including pathogen infestation,
beekeeping practices, and pesticide
exposure. Recent findings, including
a 2012 study by Lu and colleagues,
suggest CCD is related specifically to
neonicotinoids, which may impair
bees’ neurological functions.
Imidacloprid and clothianidin both
belong to this group.
Lu and his co-authors from the
Worcester County Beekeepers
Association studied the health of 18
bee colonies in three locations in
central Massachusetts from October
2012 to April 2013. At each location,
the researchers separated six
colonies into three groups – one
treated with imidacloprid, one with
clothianidin, and one untreated.
There was a steady decline in the
size of all the bee colonies through
the beginning of winter – typical
among hives during the colder
months in New England. Beginning
in January 2013, bee populations
in the control colonies began
to increase as expected, but
populations in the neonicotinoidtreated hives continued to decline.
By April 2013, six out of 12 of
the neonicotinoid-treated colonies
were lost, with abandoned hives
typical of CCD. Only one control
colony was lost – thousands of
continued on page 3