Two surveys conducted in the United Kingdom and France indicate that a class of pesticides created by Bayer CropScience could be the cause of the dwindling honey bee population seen over the past several years by commercial beekeepers.
The class of pesticides, neonicotinoids, has been in use since the 1990s according to David Fischer, Director of Environmental Toxicology and Risk Assessment for Bayer CropScience. He says that Colony Collapse Disorder, or CCD, has been a documented phenomenon since the 1800s.
"There are a lot of statements saying that these class of chemicals has been implicated in colony collapse disorder or in the decline of pollinator health," Fischer said. "That's not really true."
The disorder occurs when there is a queen bee in the hive, but few to no adult bees present. Additionally, there are no dead bees in the hive, but there are immature bees.
Fisher says that CCD is responsible for a small minority of all the honey bee losses in the United States.
"Most of the colonies that are lost by commercial bee keepers are lost for other reasons," Fischer said.
According to Fischer, factors like pathogens and parasites are more likely to disturb bee colony health. He said that the pesticides can make their way into the flowering plants on which the bees forage, but that it's not enough to risk colony health. Fischer says that the findings are questionable because the dosage of the pesticide was far more than what bees would actually encounter.
"With our neonicotinoids we're very confident that the trace levels that occur in flowering plants are not high enough to be harming bees," Fischer said.
The study conducted in Great Britain was published in the journal Science and indicated that bees exposed to the imidacloprid were 8-12% smaller than bees not exposed to the pesticide and produced 85% fewer queen bees.