The neonicotinoids are insecticides developed with
the hope of being less harmful to wildlife and beneficial insects than the
available insect killers, the pyrethroids and organophosphates. The
neonicotinoids came into widespread use with the understanding that they would
not kill beneficial insects like the honey bee and bumblebee. The use of
neonicotinoids coincides with the die-off of honey bees and significant
reductions in bumblebees. Two studies linking honey bees’ having difficulty in
navigating from flowers to the hive confirm that neonicotinoids impair bees’
senses. The studies are reported by The
Washington Post at http://www.washingtonpost.com/national/health-science/new-bee-research-details-harm-from-insecticide/2012/03/29/gIQAZrnGjS_story.html.
The studies find that bee hives exposed to low levels of neonicotinoid
insecticides have fewer bees and bumble bees produce markedly fewer queens. Bayer
CropScience, a manufacturer of neonicotinoids, calls the studies inconsistent
with their findings. Beekeepers and the Center for Food Safety petitioned the
Environmental Protection Agency to ban the use of clothianidin that the EPA
approved using Bayer’s tests.
Neonicotinoids are generally applied as a seed
coating. The systemic action of the insecticide causes the poison to be
distributed throughout the plant including the nectar and pollen, highly attractive
bee foods. Traces of neonicotinoids are taken back to the bee hive by foraging
bees. While beekeepers in the United States are taking annual honey bee colony
losses of one third each year, the effects are often more subtle than total
colony failures. Colonies are often described as simply not thriving. Bee
populations may be low; bees may have shortened life expectancies; or hives may
lack sufficient bees of appropriate foraging age. Each of these situations
leads to colonies that are susceptible to diseases and parasites. With small
populations, colonies don’t produce surpluses of honey. Bee hives used for
pollination service fail when graded according to bee population. With the ever
increasing use of neonicotinoid insecticides that have been shown to have a
detrimental effect on pollinators, the crops, lawns, and golf courses flourish
while honey bee colonies, native bees, and beneficial insects quietly disappear.
--Richard