Popular pesticide hurts wild bees in major field study
A pesticide is dramatically harming wild bees, according to a new study where experts say may help change the way the U.S. government looks at a controversial class of chemicals. But in the study, honeybees, which get trucked from place to place to pollinate major crops like almonds, didn't show the significant ill effects that their wild cousins did.
This is a finding some experts found surprising. A second study published in the same journal showed that in lab tests bees are not repelled by the pesticides and in fact may even prefer pesticide coated crops, making the problem worse.
Bees of all kinds, crucial to pollinating plants, including major agricultural crops, have been in decline for several reasons. Pesticide problems are just one of many problems facing pollinators; this is separate from colony collapse disorder, which devastated honeybee populations in recent years but is now abating, experts said.
Exposure to neonicotinoid insecticides reduced the density of wild bees, resulted in less reproduction, and colonies that didn't grow when compared to bees not exposed to the pesticide, the study found.
Scientists in Sweden were able to conduct a study that was in the wild, but still had the in-the-lab qualities of having control groups that researchers covet. They used 16 patches of landscape, eight where canola seeds were coated with the pesticide and eight where they weren't, and compared the two areas.
In areas treated with the pesticide, there were half as many wild bees per square meter than there were in areas not treated. In the pesticide patches, bumblebee colonies had "almost no weight gain" compared to the normal colonies that gained about a pound.
University of Illinois entomologist May Berenbaum, who wasn't part of either study and last year was awarded the National Medal of Science, said in an email that the studies "indicate that, at least with current technology, systemic use of pesticides is fraught with environmental problems."
The European Union has a moratorium on the use of neonicotinoids and some environmentalists are pushing for the same in the United States.