Sun, Apr 26, 2015 - Page 9 News List

Nicotine-like pesticides harm bee populations

By Karl Mathiesen  /  The Guardian

Bees may become addicted to nicotine-like pesticides in the same way humans get hooked on cigarettes, according to a new study, which was released as a landmark field trial provided further evidence that such neonicotinoids harm bee populations.

In a study published in the journal Nature, scientists from Newcastle University in England showed that bees have a preference for sugar solutions that are laced with the pesticides imidacloprid and thiamethoxam, possibly indicating they can become hooked on the chemicals.

Also published in Nature on Wednesday was a study that has been endorsed as the most conclusive evidence yet that the group of pesticides, neonicotinoids, harm wild bee populations, which include bumblebees and solitary bees.

Scientists from Lund University in Sweden carried out the first successful “real world” experiment on the effect of neonicotinoids on bees and found that wild bee populations halved around fields treated with them. Bumblebee hives stopped growing and produced less queens where the chemical was present. However, the study did not find evidence that more robust honeybees, which are used to pollinate many crops, were affected.

Maj Rundlof, the lead author of the study, said the impacts on wild bees were “dramatic.”

“I think it’s really important evidence when discussing how neonicotinoids used in real agricultural landscapes influence bees,” she said.

Sussex University bee expert Dave Goulson, who was not involved in the research, hailed the findings as hugely significant.

“At this point in time it is no longer credible to argue that agricultural use of neonicotinoids does not harm wild bees,” he said.

He said the paper was “a major step forwards in clarifying the neonicotinoid debate... This was the first fully field-realistic, well-replicated trial so far, an impressive piece of work.”

Previous field experiments on neonicotinoids have been shown to be inadequate. The current EU moratorium on the use of a group of neonicotinoids on certain crops has been criticized, particularly by the UK government, on the basis that field evidence of neonicotinoids harming bee populations has been difficult to obtain.

Nick von Westenholz, chief executive of the Crop Protection Association that represents neonicotinoid producers Bayer and Syngenta, said: “The latest studies in Nature must be seen in the context of an ongoing campaign to discredit neonicotinoid pesticides, regardless of what the real evidence shows.”

He said Rundlof’s results were questionable as the levels of the pesticide found in pollen on the bees was higher than in previous studies, suggesting that Rundlof had treated the crops herself rather than using industry-standard seeds.

Rundlof said the rapeseed in the study were treated following the manufacturers’ recommendations.

“Bayer CropScience is pleased the Swedish study demonstrates yet again there is no effect of neonicotinoids on honeybee colonies in realistic field conditions, consistent with previous published field studies,” a spokesman for the agrochemical giant said.

However, it criticized the methodology of Rundlof’s experiment and said the study offered no proof of increased bee deaths.

Rundlof said the field trial was not sensitive enough to detect anything less than a 20 percent drop in colony strength. Honeybee colonies are larger and contain far more worker bees than wild bees, meaning it would take longer for neonicotinoids to impact the hives.

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