From: Steve Williams, Care2, More from this Affiliate
Published April 27, 2015 01:07 PM

Why Bees Can't Avoid Pesticides

Pesticides such as as neonicotinoids are already under close scrutiny because research appears to show that, certainly for honey bees at least, they may interrupt the insect’s normal behaviors and they are suspected to play a part in colony collapse disorder.

One of the ways in which the pesticide industry has fought back against those claims is to point out that such studies have always involved much higher doses of neonicotinoid exposure than would occur in the wild, saying that the bees would flit between crops and flowers, some of which will have the pesticides, some of which won’t, and that even if they were negatively affected, the bees would learn to avoid particularly problematic areas.

Two separate studies published this month in the journal Nature appear to show that pesticides may have an affect not just on honeybees but other wild bees, while a second study shows that bees may have developed a preference for nicotine-like pesticides.

The first study was conducted by researchers at Lund University in Sweden. To counter claims by pesticide companies that the artificial set-up of experiments has affected past results, they attempted to create a real world experiment where they analyzed the activity of bees in eight fields of oilseed rape sown with seeds treated with the insecticide clothianidin per the manufacturer’s instructions, and eight fields that were not treated.

The researchers found that bumblebee hives stopped growing, meaning the number of bees was less than those in the untreated fields, and they produced less queens who would then go on to set up their own colonies. That said, the honeybees, which are our chief pollinators for crops, did not appear to be affected, but researcher Maj Rundlöf told Nature in a separate report that the honeybees may not be more resilient, it could just be the fact of their greater numbers. The study her team conducted could only account for a population reduction greater than 20 percent in overall colony size, so it might be that the honeybee die-off was shielded by their greater numbers but that they still suffered a potentially significant change.

This may help to clarify a long-standing issue with bee studies. Scientists had supposed that honeybees would be reflective of the general population, but that might not be true. Also, this might be why bee studies into insecticide exposure have shown mixed results when counting overall population numbers.

Continue reading at ENN affiliate, Care2.

Bee image via Shutterstock.

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