Pesticides not yet proven guilty of causing honeybee declines, new study says

Honeybee. Credit: Adam Siegel

The impact of crop pesticides on honeybee colonies is unlikely to cause colony collapse, according to a paper in the journal Science today. More research is now needed to predict the impact of widely-used agricultural insecticides, called neonicotinoids, on honeybee populations.

UK scientists from the University of Exeter and Food and Environment Agency highlight flaws in previous research (published in Science, April 2012) that predicted that neonicotinoids could cause honeybee . Neonicotinoids are among the most widely-used agricultural and honeybees ingest residues of the pesticides as they gather and pollen from treated plants.

The previous research has been cited by scientists, environmentalists and policy-makers as evidence of the future impact of these pesticides on honeybees. It is likely that the research was instrumental in the French government's recent decision to ban the use of thiamethoxam, a neonicotinoid that is the of Cruiser OSR, a pesticide produced by the Swiss company Syngenta.

However, the new paper argues that the calculations made in the research were flawed because they failed to reflect the rate at which recover from losing individuals.

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.

Lead author Dr James Cresswell of the University of Exeter said: "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 disappeared.

"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.

"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. It is vital that more research is conducted so that we can understand the real impact of neonicotinoids on , so governments can put together a proper plan to protect them from any dangers that the chemicals pose."

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Journal information: Science

Citation: Pesticides not yet proven guilty of causing honeybee declines, new study says (2012, September 20) retrieved 22 July 2019 from
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Sep 20, 2012
So the study do not deny that pesticides do cause a higher death rate for the bees but are putting into question if it will by itself cause a collapse. From what I recall the original study not only show a higher death rate, but also that the bees exposed would not grow as large and be weaker than none exposed bees.

Sep 20, 2012
This study sounds like a straw-man argument. Pesticides aren't the only cause, so therefore pesticides aren't a problem. Rubbish.
Colony collapse happens due to several accumulative causes.
- Pesticides
- Monoculture farming causing lack of plant biodiversity
- Diseases such as varoa, nosemia and foul brood
- Polution
- Climate change

Take away the pesticides and bees are still not out of danger, but that is still not a good argument for continuing pumping poisons into the environment.

Sep 20, 2012
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Sep 21, 2012
Chensheng Lu, Kenneth M. Warchol, and Richard A. Callahan from the Department of Environmental Health at the Harvard School of Public Health examined the effects of imidacloprid, a neonicotinoid pesticide, on bee colonies as part of a recent review. Part of this research involved using HFCS that had been derived from corn crops treated with imidacloprid, for which the pesticide ended up getting into the end product.

94 percent of hives treated with imidacloprid ended up dying off as a result of what appeared to be CCD, even when very minute levels of the pesticide were added. And a key culprit in this die-off was imidacloprid-tainted HFCS, which served as the delivery system for this toxic chemical...


Sep 21, 2012
I would like to know who initiated the study & where the funding came from.


Sep 22, 2012
Nom is correct and added to nom's post is moving bees arond the country spreading bee parasites, illnesses, etc from one region to the others.

Sep 22, 2012
Please note that this so-called scientific review by University of Exeter and Food and Environment Agency is funded by the Biotechnology Industry and the pesticide produced by the Swiss company Syngenta who is part of the global big six chemical cartel. "The Global Chemical Biotech Cartel - An unprecedented power over world agriculture"
It bothers me greatly that we buy "science has all the answers" and that we blindly republish the biotech industry pr spins without question.
Anyone knows that ingesting toxic, poisonous pesticides is not beneficial to any human or any species. These bees are hauled from pillar to post from one pesticide-sprayed crop to another. Their little immune systems cannot handle the lashings of pesticides we are imposing on their pollination journey.
With the battle on over pesticides and chemicals in our food supply, the biotech cartel is pulling out all stops to prove that "chemicals and pesticides are good for all species"... don't buy it.

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