For the past eight years or so, we've been hearing the term "Colony Collapse Disorder" (CCD) to refer to the seemingly spontaneous abandonment of their hives by honeybees. Bees have been abandoning their hives for centuries, but the rate at which such collapses have been observed started to increase more drastically in the 1970s, reaching alarming proportions around 2006. While numerous causes for the phenomenon have been floated, from pathogens and parasites to electromagnetic radiation and a proliferation of genetically-modified crops, new research from the Harvard School of Public Health bolsters the case that a certain class of insecticides seem to be to blame.
Working with the Worcester County Beekeepers Association in Massachusetts, the researchers exposed 12 colonies across three locations to a "sub-lethal exposure of neonicotinoids, imidacloprid or clothianidin." Neonicotinoids are popular insecticides that are chemically similar to nicotine. The scientists also observed six untreated control colonies at the same locations. The study found that all the bee colonies went about their business normally through the summer and fall, but by the end of winter six of the twelve hives exposed to the insecticide had been abandoned. One of the six control colonies was also lost due to an infestation by a fungus.
While a sample size of less than 20 colonies does not quite prove the link between certain insecticides and Colony Collapse Disorder beyond a doubt, it remains a compelling demonstration of the potential impact of neonicotinoids on honeybees. A similar study done in 2012 by some of the same researchers actually saw a much higher rate of collapse among hives treated with the insecticides, with 94 percent of the exposed colonies collapsing. Neonicotinoids are often used to prevent insects from destroying crops as early as at the time of planting, and could be carried within the plants and transferred to bees through pollen later in the growing season.
"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," said lead study author Chensheng (Alex) Lu of Harvard in a release. "Future research could help elucidate the biological mechanism that is responsible for linking sub-lethal neonicotinoid exposures to CCD… Hopefully we can reverse the continuing trend of honey bee loss."
Neonicotinoids are currently banned in the European Union. Efforts to initiate a similar ban in the United States are also underway, and the Environmental Protection Agency is currently re-evaluating the pesticides.
The study appears in the .
To jack in to my brain and get more on the latest in science, tech and innovation, follow me here on Forbes, as well as on Twitter @ericcmack and on Google+.
Source : http://www.forbes.com/sites/ericmack/2014/05/12/the-cause-of-colony-collapse-disorder-disappearing-bees-becoming-more-clear/
