Can Bees Become Addicted to Pesticides?

This is some bad news for beekeepers. Remember those harmful pesticides that conservationists, the US Fish and Wildlife Service, and even a smattering of garden retailers are trying to keep away from bees? Well it turns out that not only are they harmful to all kinds of bees, but the little buzzers are actually crazy about the stuff, flocking to the same substances that will leave them cold and alone come winter.

Colony Collapse Disorder, or CCD, is a disease that causes wintering bees to wake and suddenly abandon their hives in what looks like mass suicides.

Past studies have named the seed-coating pesticides known as neonicotinoids (neonics) as a primary cause for a recent epidemic of CCD - one that led to a major decline in US pollinator populations first noticed in 2006.

However, not everyone is convinced that neonics are actually to blame.

The 'Junky' Factor

A common argument for neonics' innocence is that if the pesticides are truly harmful, most bees would learn to avoid treated plants. After all, this is how most plants protect themselves from unwanted guests - taking on toxic elements to keep potential predators at bay.

And while bees drinking nectar isn't exactly 'predation,' it should be safe to reason that poisoning that metaphorical watering hole should have the same effect.

Unfortunately that's not the case, with recent studies showing that the number of times a bee visits a treated plant verses an untreated plant are no different. Instead, neonics supposedly affect birth rates or energy reserves. So what's going on?

Geraldine Wright, a well-published insect neuroethologist, recently decided to investigate this with several of her colleagues at Newcastle University, UK.

The resulting study, published in the journal Nature, details how bees actually prefer foods contaminated with neonic traces. (Scroll to read on...)

When Wright and her team confined honeybees (Apis mellifera) and bumblebees (Bombus terrestris) to boxes and gave them a choice between plain nectar and nectar laced with neonics, the insects showed a love for imidacloprid or thiamethoxam (two of three common neonics).

The study showed that the bees preferred pesticide-laced nectar over clean nectar regardless of concentration - an indication that the bees probably cannot taste the pesticide.

Christopher Connolly, a Reader in the Medical Research Institute at the University of Dunde, who was not involved in the study, offered his two-cents regarding these intriguing results.

He explained in a Science Media Center statement that if the bees "cannot taste the presence of these neonicotinoids... stimulus being sought may be similar to nicotine seeking behavior in humans."

A comparison that, when considering the well-known harmful nature of cigarettes, can truly hit home.

Wright even goes as far as to suggest that the neonics could, in a small way, be brainwashing the bees into preferring nectar from contaminated fields. Past studies have found inconclusive evidence that neonics may activate receptors in bee brains linked to memory and learning - a revelation with ominous implications.

However, Lin Field, Head of Biological Chemistry and Crop Protection at Rothamsted Research, is quick to point out that this work involves a lot of speculation.

"The authors suggest it is via effects on the receptor that neonics bind to, which lead to changes in 'learning'. This is very interesting," she said, "but I think this needs more work to see if it is really true and if so how it works."

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