Pesticides likely 'main culprit' in bee deaths: Harvard study
In this file photo, bees pause on a sunflower at the Agricenter in Memphis, Tenn., on Wednesday, Sept. 25, 2013. (AP Photo/Jim Weber)
Josh Elliott, CTVNews.ca
Published Saturday, May 10, 2014 2:56PM EDT
Pesticides are directly responsible for a massive decline in the bee population in North America and Europe, a new study out of Harvard University says.
The report, which is published in the June edition of the Bulletin of Insectology, concludes that corn, potato and soybean pesticides containing neonicotinoid chemicals are directly to blame for a phenomenon called colony collapse disorder (CCD).
Worker bees are thought to absorb trace amounts of the neonicotinoids during the pollination process before bringing those chemicals back to the hive. Eventually, the neonicotinoid buildup begins to neurologically impair the bees, causing them to abandon the hive.
The authors say the findings reinforce earlier studies linking neonicotinoids to a global bee die-off dating back to 2006.
"The results from this study not only replicate findings from the previous study ... but also reinforce the conclusion that sublethal exposure to neonicotinoids is likely the main culprit for the occurrence of CCD," the study states.
Erika Schuit, co-owner of Saugeen Country Honey in Elmwood, Ont., said she has no doubt neonicotinoids are responsible for the deaths of over 65 million bees at her apiary.
And based on this year’s slow spawning patterns, she said she expects to lose even more.
“They’re not building up as they would normally build up,” she told CTVNews.ca in a telephone interview on Saturday. “The queen is not laying properly.”
But the deaths aren’t just a beekeeper’s problem, Schuit said, as pollination is required for as much as 80 per cent of people’s daily diet.
“It’s everybody’s food. It’s not only farmers that feed cities; it’s pollinators that feed cities,” she said.
“We can do without pork and we can even do without honey, but we cannot do without pollinators.”
The Harvard report says neonicotinoids are responsible for the colony collapse disorder that has swept across Canada, the United States and Europe, wiping out hives like the ones at Schuit’s apiary.
Colonies affected by CCD stop producing new bees, while existing worker bees forget how to get back to the colony and die of starvation. Beekeepers typically discover CCD when they inspect their colonies in the spring, only to find a large number of the bee population is gone. Eventually, the entire hive dies.
Schuit said she’s seen bees affected by neonicotinoids flying in circles near the hive with pollen on their legs.
“Sometimes it’s pulling itself around with one or two legs and going in circles, banging into the hive, not knowing where the entrance is,” she said.
For the Harvard study, researchers examined 18 bee colonies at three different apiaries in central Massachusetts over the course of a year. Four colonies at each apiary were regularly treated with realistic doses of neonicotinoid pesticides, while a total of six hives (two at each apiary) were left untreated.
Of the 12 hives treated with neonicotinoids, six were wiped out by colony collapse disorder.
One of the six untreated colonies died from a fungus called Nosema, but the bees from that colony died inside the hive.
Neonicotinoid-treated hives stopped spawning new bees as the winter approached, and they did not resume brood-rearing when spring came around, the report said.
The study also noted that colder winters make the effects of neonicotinoids much worse.
The study replicated findings from a previous experiment to confirm its accuracy. According to the Harvard report, these findings “reinforce the conclusion that sub-lethal exposure to neonicotinoids is likely the main culprit for the occurrence of CCD.”
Researchers also found that neonicotinoid exposure does not make bees more vulnerable to disease.
Last year, pesticide manufacturers Monsanto and Bayer launched media campaigns blaming mites and fungi for the majority of bee deaths, and downplaying the role of pesticides.
“It is widely believed among the scientific community that Varroa mite is the main factor affecting the health of honey-bee colonies,” says the Bayer Bee Care Center website.
According to Schuit, pesticides just make the bees more vulnerable to the usual number of mites present in a hive.
“They can’t fight off the mites that they should, they forget how to groom themselves and each other, they forget how to feed the queen, they just lose it,” she said. “Their whole brain function is distorted.”
Schuit said pesticide companies are simply protecting themselves with sites like the Bayer Bee Care Center.
Last year, the Ontario government studied the dangers of neonicotinoids and recommended the use of corn and soy seeds not treated with pesticide. Ontario also promised one-time payments of $105 per hive for apiarists who lose colonies this year.
But the Ontario Beekeepers’ Association says each hive is worth as much as $500.
According to Schuit, farmers can’t even help if they want to. She said farmers haven’t been able to get on board with the new recommendations because untreated seed is in short supply.
“The companies have covered their backsides so well that the entire blame is going to be laid on the farmer in the end,” Schuit said.