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AKIPRESS.COM - Bee deaths reached alarming proportions in 2006 when scientists identified Colony Collapse Disorder, a syndrome of unknown cause marked by disoriented bees failing to find their way back to their hives and dying.
Beekeepers suddenly reported losing roughly a third of their colonies -- up from 15 percent in previous years.
The cause remains a subject of fierce debate and no effective antidote has been discovered. Suspicion has ranged from the varroa mite, a parasite that has infested U.S. hives since 1987, to viruses and a loss of habitat, according to Bloomberg.
In recent years, research has also linked neonicotinoids to bee mortality. A study released last week by a researcher at Harvard School of Public Health found a link between sub-lethal levels of neonics in winter bee losses. The study found that both exposed and unexposed insects survived other times of year equally well, while pesticide-treated groups fared much worse at the end of the winter, exhibiting symptoms of Colony Collapse Disorder.
This suggests that the chemicals trigger the disorder in bees, possibly by impairing their neurological functions, according to the study.
“We demonstrated again in this study that neonicotinoids are highly likely to be responsible for triggering CCD in honey bee hives that were healthy prior to the arrival of winter,” lead author Chensheng Lu, associate professor of environmental exposure biology, said in a statement.
Bayer dismissed the study, saying the colony failures were prompted in part because bees were fed artificially high levels of pesticides. The study “provides no meaningful information regarding honey bee risk assessment,” the company said in a statement.
The chemicals have been on the market for two decades, though lower-toxicity neonics such as clothianidin, marketed by Bayer as Poncho, emerged a decade ago and opened the door to widespread use in corn and soybeans, the two largest U.S. crops.
Jeff Pettis, who leads the USDA’s bee research laboratory in Beltsville, Maryland, told lawmakers in a congressional subcommittee hearing April 29 that the best action Congress could take to help beekeepers would be to better fund research into varroa, which he called a “modern plague” for bees. He characterized pesticides as a secondary concern