Pesticides such as as neonicotinoids are already under close scrutiny
because research appears to show that, certainly for honey bees at
least, they may interrupt the insect’s normal behaviors and they are
suspected to play a part in colony collapse disorder.
One of the
ways in which the pesticide industry has fought back against those
claims is to point out that such studies have always involved much
higher doses of neonicotinoid exposure than would occur in the wild,
saying that the bees would flit between crops and flowers, some of which
will have the pesticides, some of which won’t, and that even if they
were negatively affected, the bees would learn to avoid particularly
problematic areas.
Two separate studies published this month in the journal Nature appear
to show that pesticides may have an affect not just on honeybees but
other wild bees, while a second study shows that bees may have developed
a preference for nicotine-like pesticides.
The first study
was conducted by researchers at Lund University in Sweden. To counter
claims by pesticide companies that the artificial set-up of experiments
has affected past results, they attempted to create a real world
experiment where they analyzed the activity of bees in eight fields of
oilseed rape sown with seeds treated with the insecticide clothianidin
per the manufacturer’s instructions, and eight fields that were not
treated.
The researchers found that bumblebee hives stopped
growing, meaning the number of bees was less than those in the untreated
fields, and they produced less queens who would then go on to set up
their own colonies. That said, the honeybees, which are our chief
pollinators for crops, did not appear to be affected, but researcher Maj Rundlöf told Nature in a separate report
that the honeybees may not be more resilient, it could just be the fact
of their greater numbers. The study her team conducted could only
account for a population reduction greater than 20 percent in overall
colony size, so it might be that the honeybee die-off was shielded by
their greater numbers but that they still suffered a
potentially significant change.
This may help to clarify a
long-standing issue with bee studies. Scientists had supposed that
honeybees would be reflective of the general population, but that might
not be true. Also, this might be why bee studies into insecticide
exposure have shown mixed results when counting overall population
numbers.
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