Large study links key pesticide to weakened honeybee hives

June 29, 2017
FILE - In this May 27, 2015, file photo, volunteer Ben Merritt, a graduate student at the University of Cincinnati, checks honeybee hives for queen activity and performs routine maintenance as part of a collaboration between the Cincinnati Zoo and TwoHoneys Bee Co., in Mason, Ohio. A common and much-criticized pesticide dramatically weakens already vulnerable honey bee hives, according to a new massive in-the-field study in three European countries. For more than a decade, the populations of honey bees and other key pollinators have been on the decline. Other studies, mostly lab experiments, have pointed to problems with the insecticides called neonicotinoids, but the new research done in Britain, Hungary and Germany is the largest field study yet.(AP Photo/John Minchillo, File)

WASHINGTON (AP) — A massive new study in three European countries finds a common pesticide dramatically weakens already vulnerable honeybee hives.

For their experiment, researchers planted fields of rapeseed, which is made into cooking oil. Some of the fields were planted with seeds treated with the class of insecticides called neonicotinoids, others with untreated seeds. The researchers followed bees from the spring of 2015 when the seeds flowered to the following spring when new bees were born.

In Hungary and Britain, the hives that had bees foraging around insecticide-treated plants had a more difficult time surviving the winter. In Germany, where the bees are generally healthier, there was no noticeable harm to the bees from the insecticide.

The study is in Thursday’s journal Science.