Published August 29, 2016
Back in the mid-1940s, the U.S. government undertook a mass fumigation campaign using the highly toxic organochloride pesticide DDT (dichlorodiphenyltrichloroethane)....
— William Wilberforce
The buzzword has been that neonicotinoids, the most widely used pesticide on earth, may be a significant contributor to the growing problem of the disappearing honeybee. Discussing two studies from the journal Nature, NPR correspondent Allison Aubrey recently reported that part of the reason the neonics are so widely used is that they are easy to use. There is no spraying, no cloud of pesticide in the air, no toxic fumes. You only have to buy the right treated seeds, and then plant as usual.
The seeds are coated with the neonicotinoid pesticide, and when planted, the water-soluble pesticide is absorbed by the developing plant and “protects the tissues” from the inside out. Unfortunately, the pesticide is ultimately expressed in the flowers, neonic residues show up in the nectar and pollen months later, and the bees, which feed on those very same nectars and pollens, are exposed to the pesticide.
As the name implies, neonicotinoids are derived from nicotine and act as a neurotoxin, or nervous system poison. It has been proposed that the bees might be repelled by plants grown from the treated seeds and would instinctively avoid them. One of the studies discussed in the NPR story, however, suggests that is not the case. Researchers conducted a laboratory experiment to determine the types of foods bees are attracted to, and they found that rather than avoid the poison, the bees preferentially chose neonicotinoid-treated water over plain sugar water.
Data indicate that the bees are not able to taste the neonic but they are nevertheless choosing the pesticide-treated water over the regular sweet syrup. The implication is that the bees may be getting a “buzz” from the toxin—similar to the reaction humans get from nicotine—and it is causing them to choose a food that will ultimately do them harm. Scientist Nigel Raine says it might be the same pathway; they are receiving positive reinforcement.
A second study shows a negative impact of the neonicotinoid-treated seed/plants on populations of wild bees, though the same negative effect was not observed in honeybee colonies. Scientists at Bayer CropScience, a major producer of neonicotinoids, suggest this confirms their view that neonics do not impact honeybees in regular field conditions. But enough questions have been raised that the European Union, the government of Ontario, Canada and the United States Environmental Protection Agency have proposed restrictions on the use of neonicotinoid pesticides.
The loss of honeybees represents more than simply an increase in the price of honey. As one of our most important pollinators, honeybees ensure the supply of of many fruits and vegetables. The demise of the honeybee would irrevocably compromise the world’s food supply.
Read the full April 22, 2015 article at Buzz Over Bee Health: New Pesticide Studies Rev Up Controversy on NPR.