Serious flaws in recent US study on neonicotinoids

Scientific value of findings is limited

May 22, 2014
Serious flaws in recent US study on neonicotinoids

Serious flaws in recent US study on neonicotinoids

Earlier this month, Harvard researchers Chensheng Lu et al. published a study claiming that chronic neonicotinoid exposure causes Colony Collapse Disorder (CCD) in honeybees.

Colony collapse disorder is not a common, global phenomenon, but specific to the USA; in Europe, for instance, colony losses with CCD symptoms are exceptional. Even in the USA, the vast majority of colony losses are not caused by this and many professional apiarists have never seen a single case of CCD.
 The scientific value of the study is limited, says

Dr. Julian Little, spokesman for the Bayer Bee Care Center:  “Dosages are far removed from the reality in the field. The researchers were feeding honeybees with dose rates at 10, possibly nearer 100, times what they would normally encounter in the field.”

Not only were the doses really high, they were also given over 13 consecutive weeks – far longer than the 1 to 3 week exposure seen following normal agricultural uses, explained Julian Little.  “And to try to link their results to CCD is frankly bizarre since the symptoms they describe in their study do not resemble CCD in the US in the slightest”.

First media reactions share the view of Bayer CropScience. Under the title “Bad Science Doesn't Help Bees”, Lisa Beyer at BloombergView states that Lu's research distracts attention from the real causes of bee deaths and that his trials used dosages far in excess of anything bees would encounter in the fields. She comments that Lu’s study is getting largely uncritical media attention, which strengthens the call of the US activists to ban CNIs. She argues that such a ban would be a mistake: “It would compel U.S. farmers to use older pesticides that haven't been subjected to bee studies and may be more hazardous to cultivated bees, not to mention wildlife and humans.”

In its online edition, The New York Times quotes Dr. Dennis van Engelsdorp, entomologist at the University of Maryland, as saying that Dr. Lu and his colleagues gave the bees doses far beyond what they would encounter in nature, and over longer periods of time, so the new study only shows that “high doses of ‘neonics’ kill bees – which is not surprising.”
As a result, unfortunately, this latest study conducted by Dr. Lu repeats the fundamental flaws seen in his previous research and provides no meaningful new information regarding honey bee risk assessment.

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