The on-line articles reported chemicals known as neonictotinoids may have a detrimental effect on pollinating bees. According to Science, "in bumble bees, exposure to such chemicals leads to a dramatic loss of queens and could explain the insects' decline. In honey bees, another insecticide interferes with the foragers' ability to find their way back to the hive."
The article states: "We exposed colonies of the bumble bee Bombus terrestris in the lab to field-realistic levels of the neonicotinoid imidacloprid, then allowed them to develop naturally under field conditions. Treated colonies had a significantly reduced growth rate and suffered an 85% reduction in production of new queens compared to control colonies. Given the scale of use of neonicotinoids, we suggest that they may be having a considerable negative impact on wild bumble bee populations across the developed world."
Bayer Crops Sciences quickly responded: "All new research involving bee health is to be welcomed, but care must be taken in drawing conclusions based on relatively artificially-generated results, particularly when compared to the weight of evidence from previous studies. In this study, bees were unrealistically exposed to imidacloprid and then allowed to develop in semi-field conditions."
Science also stated: "Nonlethal exposure of honey bees to thiamethoxam (neonicotinoid systemic pesticide) causes high mortality due to homing failure at levels that could put a colony at risk of collapse. Simulated exposure events on free-ranging foragers labeled with an RFID tag suggest that homing is impaired by thiamethoxam intoxication. These experiments offer new insights into the consequences of common neonicotinoid pesticides used worldwide."
Bayer's response: "The study on bumble bees in the UK provides useful information as part of the growing body of research regarding this important pollinator. Although the doses are higher than what would typically be found in the environment, the authors noted a decrease in queen production compared to the untreated colonies. These results are not consistent with previous studies, which showed no adverse effects on bees in field-relevant concentrations."
Last week the Environmental Protection Agency received a petition by Beyond Pesticides, Pesticide Action Network, Center for Food Safety, the International Center for Technology Assessment and a group of bee keepers, concerning the insecticide clothianidin.
The petition asks federal regulators to suspend use of a pesticide they say harms honeybees. The group is urging EPA to ban clothianidin, one of a class of chemicals that act on the central nervous system of insects.
Bayer's response: "The petition appears to present no new arguments or data supporting their challenge of EPA's registration of clothianidin products, which was first approved in 2003."
Chlothianidin is the active ingredient in Poncho seed treatments and is approved by the EPA for use on corn, cotton, sorghum, soybeans and sugar beets.
Beginning in October 2006, some beekeepers began reporting losses of 30%-90% of their hives, according to USDA's Agricultural Research Service. While colony losses are not unexpected during winter weather, the magnitude of loss suffered by some beekeepers was highly unusual.
From the ARS website: "This phenomenon, which currently does not have a recognizable underlying cause, has been termed "Colony Collapse Disorder" (CCD). The main symptom of CCD is simply no or a low number of adult honey bees present but with a live queen and no dead honey bees in the hive. Often there is still honey in the hive, and immature bees (brood) are present."
ARS scientists and others are in the process of carrying out research to discover the cause(s) of CCD and develop ways for beekeepers to respond to the problem.
Backyard gardener fights insecticide
Susan Mariner, a third generation backyard gardener from Virginia, has launched a campaign urging the EPA to ban the sale neoniconitoids.
"The EPA needs to step up to protect the environment and the bees who provide essential pollination for much of the nation's food," says Mariner. "As a mother trying to pass on the tradition of backyard gardening, my family has already seen an alarming decline in the wild bee population.
"There are multiple sources which point to products like Clothianidin as deadly and dangerous insecticides to bees," Mariner adds. "If the EPA does not ban the sale of Bayer's environmentally destructive products, I worry what will happen in the future to gardeners, farmers, and the fruits and vegetables we eat."
Mariner says the EPA scientists have discredited Bayer's previous studies of neoniconitoids, pointing to "colony collapse disorder," which has reportedly resulted in the creation of 85% fewer bee hives in recent years.
Mariner launched her petition on Change.org, a social network.