Americans like their sweets. And the food industry's go-to sweetener—high-fructose corn syrup—can be found in hundreds of foods and drinks, including everything from bread and kid cereals to juices and soda. The man-made sweetener has been blamed for America's rising obesity epidemic, but it's now implicated in colony collapse disorder, a mysterious disease that's wiping out honeybees.
So how is this happening?
High-fructose corn syrup often harbors traces of a chemical seed coating used to deter pests in the fields. And just like food companies, beekeepers have gotten addicted to the stuff because it boosts honey production. Many supplement their bees' diet with the harmful sweetener, but in doing so, they're exposing bees to a toxic chemical insecticide.
A new study from Harvard researchers suggests it's not the high-fructose corn syrup, per se, but the traces of imidacloprid, a neonicotinoid pesticide, that's harming the bees.
As if that exposure isn't enough, bees also come into contact with imidacloprid through plant pollen. Although imidacloprid is used as a seed coating for most corn in this country, it moves throughout the plant and winds up in the pollen because it is a systemic pesticide.
The Harvard research, to be published in the June edition of the Bulletin of Insectology, is the latest in a string of studies providing "convincing evidence" that imidacloprid is causing colony collapse disorder, an epidemic that threatens the food supply, since honey bees pollinate $20 billion worth of food crops a year.
"In terms of linking imidacloprid to CCD, the results from our study are indisputable," says lead study author Chensheng Lu, PhD, associate professor of environmental exposure biology at Harvard University. "The survival of hives that are not treated with imidacloprid augments the conclusion."
In the study, researchers monitored four different bee areas over a 23-week period. Each area contained four hives treated with various levels of imidacloprid and one untreated hive. After three months, the bees were still alive. But within 6 months, all but one of the imidacloprid-treated hives were largely wiped out.
Larger doses of the chemical pesticide caused hive collapses, but interestingly, so did amounts smaller than what's typically found in cornfields.
"The significance of bees to agriculture cannot be underestimated," says Lu. "And it apparently doesn't take much of the pesticide to affect the bees. Our experiment included pesticide amounts below what is normally present in the environment.
Lu says that it's not yet clear how imidacloprid in the food chain could be affecting humans.