Pesticides May Be Contributing to Declining Bee Populations

Pesticides have long been suspected as one of possibly many culprits in the decline in the world's bee population, but until the publication of two new studies, it wasn't clear how or why.

Released in Thursday's issue of the journal Science, the studies examine the effect of some of the world's most common pesticides on the brain functioning of bees.

One of them, led by French researchers, found that when honey bees were exposed to nonlethal levels of thiamethoxam, mortality rates rose high enough that, as the scientists state in the study's abstract, it "could put a colony at risk of collapse." The reason for this, according to the researchers, was that those exposed to the pesticide struggled to find their way home after leaving the hive to forage.

In the second study, scientists noted that bumblebees treated with the pesticide struggled to propagate. In total, the treated colonies saw an 85 percent reduction in production of new queens when compared to the control colonies.

As a a result, the researchers stated in the study that the use of the pesticides examined - in both cases neuro-active chemicals related to nicotine - may be causing a "considerable negative impact" on wild bumble bee populations throughout the developed world.

"I personally would like to see them not being used until more research has been done," David Goulson, author of the bumblebee paper, told The New York Times. "If it confirms what we've found, then they certainly shouldn't be used when they're going to be fed on by bees.";

The studies, however, are not without their critics.

Ian Boyd, chief scientist at the UK Department for Environment, Food and Rural Affairs, told the BBC that before any kind of restriction goes in place, it will have to be "based on more realistic field trials."

One ecotoxicologist from Bayer CropScience, a manufacturer of some of the pesticides, believes the dose given to the honeybees was unrealistically large, according to The New York Times.

Julian Little is the communications and government affairs manager from the same company. The studies, he told BBC, are not necessarily relevant out in the field.

"If you take an insecticide and you give it directly to an insect, I can gaurantee that you will have an effect - I am not surprised at all that this is what you will see." he said. "What is really important is seeing what happens in real situation - in real fields, in real bee colonies, in real beehives, with real bee keepers."