Study challenges pesticide link with bee colony collapse

Earlier research may have some flaws

Honeybees and bumblebees are in big trouble. Photo by Bob Berwyn.

By Summit Voice

SUMMIT COUNTY — Honeybees may be dying from ingesting remnants of insecticides, but that in itself may nor be causing the widespread colony collapse being observed in many areas, according to new research published in the journal Science.

Starting in about 2006, beekeepers started reporting declines of 30 to 90 percent in many of their hives, in part due to a phenomenon known as Colony Collapse Disorder.

There are several studies showing that ingestion of pesticides leads to direct mortality, as well as a decline in the number of queen bees, which are critical to the establishment of new colonies following the winter die-off.

The latest study contradicts at least some of the earlier research that suggests  widespread use of neonicotinoid insecticides is wiping out honeybees.

Partly based on that research, the French government earlier this year banned the use of thiamethoxam, a neonicotinoid that is the active ingredient of Cruiser OSR, a pesticide produced by the Swiss company Syngenta.

Scientists from the University of Exeter and the UK Food and Environment Agency said the earlier study was flawed because it underestimated birth rates, thus failing to reflect the rate at which honeybee colonies recover from losing individuals.

“I am definitely not saying that pesticides are harmless to honeybees, but I think everyone wants to make decisions based on sound evidence, and our research shows that the effects of thiamethoxam are not as severe as first thought,” said  Dr. James Cresswell, of the University of Exeter.

“We know that neonicotinoids affect honeybees, but there is no evidence that they could cause colony collapse. When we repeated the previous calculation with a realistic birth rate, the risk of colony collapse under pesticide exposure disappeared,” Creswell said.

The previous research, led by French scientist Mikaël Henry, showed that the death rate of bees increased when they drank nectar laced with a neonicotinoid pesticide, thiamethoxam. It calculated that this would cause their colony to collapse. The research published today explains how the calculation may have used an inappropriately low birth rate.

“We do not yet have definitive evidence of the impact of these insecticides on honeybees and we should not be making any decisions on changes to policy on their use,” Creswell said. “It is vital that more research is conducted so that we can understand the real impact of neonicotinoids on honeybees, so governments can put together a proper plan to protect them from any dangers that the chemicals pose.”


2 thoughts on “Study challenges pesticide link with bee colony collapse

  1. If only the researcher was not paid by Syngenta and it data based on three colony at the beginning of last century, maybe then it would be worth something

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