Ouch. This tells us that our bees after a certain modest threshold
of exposure must simply get lost. Even worse, two pesticides used
naturally in tandem produce cumulative damage. It is not good news
and this is ample evidence to completely redress the whole pesticide
protocol and work actively to stop exposure.
The science here is actually worse news than we had actually
anticipated. Two groups present the same impact. Without doubt, the
anti mite protocol needs to be completely revisited.
Unfortunately this movie has not ended yet. Another item tells us
that the decline is continuing and possibly heading for a collapse of
general pollination. It is upsetting and will not end until a class
action suit ground Bayer and others with commensurate damages.
Pesticide
combination affects bees' ability to learn
by Staff Writers
London, UK (SPX) Apr 02, 2013
Two new studies have
highlighted a negative impact on bees' ability to learn following
exposure to a combination of pesticides commonly used in agriculture.
The researchers found that the pesticides, used in the research at
levels shown to occur in the wild, could interfere with the learning
circuits in the bee's brain. They also found that bees exposed to
combined pesticides were slower to learn or completely forgot
important associations between floral scent and food rewards.
In the study published
March 27, in Nature Communications, the University of Dundee's Dr
Christopher Connolly and his team investigated the impact on bees'
brains of two common pesticides: pesticides used on crops called
neonicotinoid pesticides, and another type of pesticide, coumaphos,
that is used in honeybee hives to kill the Varroa mite, a parasitic
mite that attacks the honey bee.
The intact bees'
brains were exposed to pesticides in the lab at levels predicted to
occur following exposure in the wild and brain activity was recorded.
They found that both types of pesticide target the same area of the
bee brain involved in learning, causing a loss of function. If
both pesticides were used in combination, the effect was greater.
The study is the first
to show that these pesticides have a direct impact on pollinator
brain physiology. It was prompted by the work of collaborators Dr
Geraldine Wright and Dr Sally Williamson at Newcastle University who
found that combinations of these same pesticides affected learning
and memory in bees.
Their studies
established that when bees had been exposed to combinations of these
pesticides for 4 days, as many as 30% of honeybees failed to learn or
performed poorly in memory tests. Again, the experiments mimicked
levels that could be seen in the wild, this time by feeding a sugar
solution mixed with appropriate levels of pesticides.
Dr Geraldine Wright
said: "Pollinators perform sophisticated behaviours while
foraging that require them to learn and remember floral traits
associated with food. Disruption in this important function has
profound implications for honeybee colony survival, because bees that
cannot learn will not be able to find food."
Together the
researchers expressed concerns about the use of pesticides that
target the same area of the brain of insects and the potential risk
of toxicity to non-target insects. Moreover, they said that exposure
to different combinations of pesticides that act at this site may
increase this risk.
Dr Christopher
Connolly said: "Much discussion of the risks posed by the
neonicotinoid insecticides has raised important questions of their
suitability for use in our environment. However, little consideration
has been given to the miticidal pesticides introduced directly into
honeybee hives to protect the bees from the Varroa mite. We find that
both have negative impact on honeybee brain function."
"Together, these
studies highlight potential dangers to pollinators of continued
exposure to pesticides that target the insect nervous system and the
importance of identifying combinations of pesticides that could
profoundly impact pollinator survival." 'Cholinergic pesticides
cause mushroom body neuronal inactivation in honeybees'. Nature
Communications.
'Exposure to multiple
cholinergic pesticides impairs olfactory learning and memory in
honeybees.' J Exp Biol Advance Online Articles. 7 February 2013 as
doi:10.1242/jeb.083931. Access the most recent version here
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