Researchers performing a massive field study in three European countries have discovered what bee lovers in North Carolina say they already know: Exposing bees to common pesticides weakens honeybee hives.
The study — performed in Britain, Hungary and Germany, and published Thursday in the journal Science — is the largest yet into the effects of insecticides called neonicotinoids. Researchers reported finding that bees exposed to grains whose seeds were treated with the substance were more likely to die off, depleting the number of worker bees needed to maintain hives.
Neonicotinoids appear in chemicals used for commercial and home use.
Richmond County resident and beekeeper David Auman finds the results of the study unsurprising. He says people hate a lot of the things that pollinators such as bees love — dandelions and wild growth — so they turn to pesticides.
“We like everything clean,” said Aumon, who for a decade has been president of the Richmond County Beekeepers Association. So we mow our grass and eliminate our dandelions.
As a result of people’s hatred for unwelcome plant life — weeds — the populations of honeybees and other key pollinators have been on the decline for more than a decade, leaving scientists to figure out what’s behind the drop: disease, parasites, poor diet or pesticides?
Most lab studies have focused on neonicotinoids, which researchers say harm pollinators’ nervous systems. Pesticide producers dispute that.
Several American states have considered legislation to protect pollinators, including North Carolina, where a pollinator-protection bill died in committee this year.
Last year, Maryland passed a law limiting the use of neonicotinoids to certified applicators, farmers and veterinarians. The law will take effect next year.
Europe banned neonicotinoids in 2013, so researchers needed a special exemption to perform their three-country study.
The European and a Canadian study also reported in Science show that neonicotinoids harm bees but still may not quite be the leading cause of bee loss. Disease also can factor in.
In this area, Aumon said, mites are a particular plague.
Researchers performing the European study planted 7.7 square miles of rapeseed, which is used to make canola. Some fields were planted with seeds treated with the insecticide, 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.
The bee hives in Hungarian and British fields that used pesticide-treated seeds fared worse through the next winter, the researchers found. But in Germany, the bees didn’t seem harmed. Hives there were generally healthier to start with, and the German bees evidently had broader diets — they didn’t eat mainly rapeseed.
Earlier this year, back in Richmond County, Aumon planted several acres of buckwheat. It’s blooming now.
“I could actually hear it buzzing if I walked close to it,” he said.
Philip Perkins, another Richmond County beekeeper, planted a field of clover and granola in the Richmond County Industrial Park in 2015 — which was later cleared to make room for RSI Home Products.
He told the Daily Journal at the time — and again earlier this year, while removing a colony of bees from a Hamlet home — that he believes pesticides and manipulated crops, with built-in pesticides, are responsible for hurting the honeybees.
“If we could make local gardeners just understand that if you’re going to poison on the garden, do it after 6 in the afternoon,” he said in April. “Honey bees go home around 5 or 6 o’clock, poisons die out overnight.”
Most bees that get into poison never make it to the hive, he added. If they do, they take it back to the hive and infect the rest of the colony.
The Raleigh News & Observer reported in 2008 that German beekeepers filed a complaint against Bayer CropScience — which has its U.S. headquarters in Research Triangle Park — alleging the company knew that its pesticides had a negative impact on bees.
Bayer insisted that the impact of clothianidin on bees was minimal.
However, a 2003 report from the Environmental Protection Agency reads in part: “Clothianidin is highly toxic to honey bees on an acute contact basis…It has the potential for toxic chronic exposure to honey bees, as well as other non-target pollinators, through the translocation of clothianidin residues in nectar and pollen. In honey bees, the effects of this toxic chronic exposure may include lethal and/or sub-lethal effects in the larvae and reproductive effects in the queen.”
According to Perkins, it costs $110 to replace a colony lost to Colony Collapse Disorder and it will take a year and a half before the bees are productive.
Information from the Associate Press was used in this report.