A commonly used type of pesticide has been found to dramatically harm wild bees, according to new studies. Experts said that this finding may change the way the government views controversial classes of chemicals.
The problem has been detailed in two studies that researchers published in the journal Nature.
For the first study, the researchers examined the harmful effects of a pesticide known as neonicotinoids, which are used on rapeseeds to protect them against flea beetles, and found that they have a negative impact on wild bees. Such effect is considered a serious concern because these insects, which include bumblebees and solitary bees, have a crucial role in crop pollination.
The researchers likewise found that, aside from the insecticide's effect on the growth and reproduction of bumblebee colonies, there were fewer wild bees on treated rapeseed fields. No negative effect on the growth of honeybee colonies was, however, observed.
Although scientists are already aware that the most common pesticides tend to be the most harmful to the wild bees, experts said that the findings may help influence actual change. The researchers believe that their work will have an effect on how government agencies view chemicals when green lighting them for use.
"This paper has the potential of really shifting the conversation," said University of Maryland entomologist Dennis vanEngelsdorp. "Neonics may have a very dramatic effect on these non-managed pollinators in the environment. This is the most definitive work I've seen in the area."
The second study also showed that the pesticides do not repel the bees, with the insects even preferring crops that are pesticide coated, which makes the problem worse. The researchers likewise found that exposure to neonicotinoid pesticides is associated with less reproduction and reduces the density of wild bees. The colonies do not also grow when compared with bees with no pesticide exposure.
The researchers found that, in areas treated with pesticides, there were only half as many wild bees per square meter compared with those in areas that were not treated. Bumblebee colonies were found to have nearly no weight gain in the pesticide patches compared with the normal colonies that have weight gain of about a pound.
For the study, researchers from Sweden used and compared 16 patches of landscape, eight of which had canola seeds that were coated with pesticide and the other eight where they weren't.
Photo: Bob Peterson | Flickr
