Commonly Used Pesticides May Attract -and Kill- Honey Bees

By Sasha Figel

Across the United States and many other countries, beekeepers have reported losing more than half of their hives in a single year. Anecdotes from around the world tell of an increase in honeybee deaths, leaving scientists and beekeepers searching for answers.

Honey bees are extremely important to our economy, pollinating at least 90 crops in North America[1], but recent research has indicated that we have been harming the very creatures that provide us with food. The use of neonicotinoids, a type of insecticide, has been implicated in the deterioration of bee hives, to the point that some neonicotinoids were banned in the European Union. To make matters worse, honeybees may be attracted to the lethal insecticides.

A field of oilseed rape is sprayed with insecticides

A field of oilseed rape is sprayed with insecticides. “Chafer – Sentry-7611” by Chafer Machinery is licensed under CC BY 2.0

Neonicotinoids are a class of insecticide that affects the central nervous system, resulting in paralysis and death in insects. Most research points to neonicotinoids as a cause of bee death and colony collapse disorder, but effects from residue in pollen and nectar remain uncertain[2]. Researchers haven’t yet determined if the insecticide reaches a high enough concentration in pollen and nectar to harm bees.

Earlier this year, Sébastien C. Kessler, a researcher at Newcastle University, authored a paper published in Nature documenting honeybees’ (and bumblebees’) preference towards foods containing neonicotinoids[3]. He found that when given a choice between sugar water and sugar water containing one of three widely used neonicotinoids, bees had no preference for the sugar water over the laced sugar water. In fact, bees preferred solutions with neonicotinoids in all experiments except at the highest concentrations, although even the lower concentrations had negative effects on the bees’ ability to function.

Critics of pesticide bans have argued that bees could choose to avoid plants that have pesticides. However, if the bees prefer the plants with pesticides, as Kessler’s study suggests, it is up to us to reduce our pesticide use so that bees continue to pollinate the number of plants that we are accustomed to.

Additionally, previous estimates of the impacts of pesticide use on bee hives will be lower than actual impacts. By bringing back foods with a preference towards neonicotinoid-laced foods, the pesticide concentrations in hives will be higher than pesticide concentrations on crops. This impacts the well being of bees, as studies have shown that neonicotinoids impair their olfactory learning and memory.

If neonicotinoids are so dangerous to bees, why do bees prefer them? Geraldine Wright, a professor at Newcastle University and a co-author on the paper, may have an answer for us. “Neonicotinoids target the same mechanisms in the bee brain that are affected by nicotine in the human brain.” In other words, bees may get a similar feeling from neonicotinoids as humans get from cigarettes. The next step will be finding out if the bees are becoming addicted to neonicotinoids, and if they are becoming addicted, what the implications of that could be[4].

As with many conservation issues, we must decide between acting now with incomplete data and acting later when bees might be more impacted. As mentioned above, the European Union banned some neonicotinoids already, opting to act without complete data on the effects of neonicotinoids. These bans on pesticide use are being met with heavy criticism from farmers and the pesticide industry. Without neonicotinoids, farmers must resort to older technologies, which are typically less efficient and more expensive[5]. Many farmers would rather continue to use neonicotinoids until there is concrete evidence that they are harming bees. Kessler’s research has added one more piece of evidence towards the negative effects of neonicotinoids, but the data is not yet solid enough to convince many farmers.

Farmers aren’t the only people using insecticides. Many common garden products also contain neonicotinoids. By avoiding products containing ingredients such as imidacloprid, clothianidin, thiamethoxam, acetamiprid, and dinotefuran, you can help protect the pollinators that live around you[6]. All it takes is checking the active ingredients before you buy an insecticide.

Honeybee health affects all of us. If we stop using neonicotinoids, we can protect the bees, protect our produce, and protect ourselves.


References:

[1] Fact Sheet: The Economic Challenge Posed by Declining Pollinator Populations.The White House. The White House, 20 June 2014. Web. 15 Sept. 2015.

[2]Chemicals Implicated.” Issues: BEE Protective: Pollinators and Pesticides: Chemicals Implicated — Beyond Pesticides. Web. 15 Sept. 2015.

[3] Kessler, Sébastien C., et al. “Bees prefer foods containing neonicotinoid pesticides.” Nature (2015).

[4] Briggs, Helen. “Bees ‘get a Buzz’ from Pesticides – BBC News.” BBC News. 23 Apr. 2015. Web. 15 Sept. 2015.

[5] Amelinckx, Andrew. “Neonicotinoid Ban Costs UK Farmers $30 Million, No One Knows If It Actually Saves Bees.Genetic Literacy Project. 14 Sept. 2015. Web. 15 Sept. 2015

[6]Help the Honey Bees!Center for Food Safety. Apr. 2013. Web. 20 Oct. 2015.

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This entry was posted in Conservation Biology Posts, Conservation Editorials 2015. Bookmark the permalink.

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