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Wednesday, 10 December 2008 14:20

The Naturalist's Corner

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Bees do it and die

Honeybees are not native to the States. But these prolific pollinators arrived with the earliest settlers. With the changing agricultural landscape, i.e., thousands of acres of monoculture crops and the decimation of native pollinators through habitat loss, rampant pesticide application and direct competition with this European immigrant, the honeybee has been crowned king of pollinators across the U.S.

The national honeybee industry is a $15 billion a year business. And it’s more than just honey and bee balm. One report suggests that honeybees are responsible for 30 percent of all food sold in today’s grocery stores.

So with all our pollen in one hive, so to speak, it makes it really scary when beekeepers (apiarists) across the country start reporting a mysterious disappearance of from 30 to 90 percent of their hives. According to researchers at North Carolina State University beekeepers have, in the past and still today, occasionally suffer dramatic hive losses. These losses have been known as autumn collapse, spring dwindle, fall dwindle disease, May disease and various other names. But these incidents have never appeared as widespread, systematic or similar in appearance as the 2006 event.

That event was so striking that a new sexy name was invented to describe it — Colony Collapse Disorder or CCD. Symptoms of CCD include an insufficient number of bees left in the hive to maintain the brood in the colony; a workforce devoid of older bees; the presence of a queen; the colony’s reluctance to consume food supplied by the apiarist; few or no dead bees around the hives and the presence of capped brood. The colony of older worker bees has simply disappeared.

Any beekeeper can tell you that honeybees already suffer from a litany of lethal threats including different kinds of mites, viruses and fungal infections. But beekeepers and scientists across the country and around the globe are pointing fingers at a new suspect.

The alleged culprit is a synthetic nicotine known as imidacloprid used in a plethora of pesticides around the world. Imidacloprid has been patented since 1988 but only gained widespread use in the past few years when pesticides containing diazinon were banned and pulled off the shelves. Bayer the original patent holder markets imidacloprid through many trade names but the pesticide Merit is the most common. Other products that contain imidacloprid include Admire, Premise, Muralla, Leverage, Trimax and many more.

While Bayer denies any of its products cause CCD, according to a recent story in the High Country Press by Sam Calhoun, the company has paid out $70 million to beekeepers in France and at least 16 European countries have banned imidacloprid. Another neo-nicotinoid, clothianidin, has also been implicated in CCD and was recently banned in Germany.

One of the things that makes it so difficult to point to a causal factor regarding CCD is that there are no dead bees at the hive. But this, in itself, is anecdotal evidence of neo-nicotinoids. Low doses of neo-nicotinoids may not kill bees and other insects outright but it disorients them and causes abnormal behavior. Beekeepers say bees forget where the hive is. They also say the chemicals affect the bees’ ability to “dance.” The bee dance is how bees communicate where to find nectar. When the dance is corrupted bees don’t know where to go.

A study on wasps by entomologist Dr. Richard McDonald found that wasps exposed to imidacloprid became so disoriented that they spent the rest of their lives grooming themselves. Bayer even notes on its termite pesticide containing imidacloprid that insects that survive the initial treatment will be killed when the product, “confuses and distresses the colony to cause them to be killed through other diseases.”

Studies also show that imidacloprid, in the landscape, is long lived and disperses quickly especially when used for foliar spraying and/or soil drenching. This may be of special concern in the Southern Appalachians and other areas in the east where Merit is recommended for combating the Hemlock wooly adelgid.

British researcher David Buffin notes that imidacloprid is also deleterious to birds, fish, freshwater crustaceans and a host of beneficial insects.

Don Hendershot can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it.

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