Bees Get Hooked on Pesticides Like People Get Hooked on Cigarettes

A recent study reveals some startling news about the effects some pesticides have on bees, and it’s not good news. According to researchers from Imperial College London and Queen Mary University of London, bees get addicted to some pesticides in the same way that humans get addicted to nicotine. [1]

Over time, bees start to enjoy the taste of pesticide-laced food, eventually eating more and more in what the authors of the study describe as addictive behavior.

The team specifically looked at neonicotinoids, a class of pesticides linked to bee deaths and overall poor health. Research shows that when bumblebees are exposed to neonicotinoids, the pollinators’ growth rate significantly drops, and the production of new queens declines by 85% compared with colonies not exposed to the chemicals. Neonicotinoids are banned in the European Union (EU).

Neonicotinoids are still widely used in the United States, but some large retailers have stopped selling the pesticides or have vowed to phase out their use.

For the study, the team tracked 10 bumblebee colonies over 10 days. Each colony was provided 3 types of feeders:

  • 1 containing no pesticide
  • 1 containing a low amount of pesticide
  • 1 containing a higher amount of the product

The researchers counted how many times the bees visited each feeder and the amount of food they consumed. In addition, they changed the position of the identical feeders halfway through the experiment, to see which one the bees preferred.

At first, the bees chose the pesticide-free feeders. But eventually, they started eating from the laced feeders more and more and sought out the “clean” and low-dose pesticide feeders less. [1]

Researcher Andres Arce said: [2]

“We also saw that when the position of the feeders was changed, the bees responded and would still visit the feeders containing the pesticides – which indicates that they could detect the pesticide and would track it.”

In a statement, Richard Gill, lead researcher on the study and a lecturer at Imperial College London, explained that pesticides work in the bodies of bumblebees similarly to the way nicotine works in the human body. [1]

“Interestingly, neonicotinoids target nerve receptors in insects that are similar to receptors targeted by nicotine in mammals. Our findings that bumblebees acquire a taste for neonicotinoids ticks certain symptoms of addictive behavior, which is intriguing given the addictive properties of nicotine on humans, although more research is needed to determine this in bees.”

Actually, this information isn’t so new.

WATCH: Director of Pesticide Action Network Explains How Neonicotinoids Work

Unlike past studies that only offered food containing pesticides to bees, Gill and his colleagues wanted to test bees’ reaction to neonicotinoids in the wild, where they would be exposed to both clean food and contaminated food.

Gill explained: [2]

“We originally wanted to know if the bees could detect the presence of this class of pesticide and, if given enough time, learn to avoid food containing the pesticide.

In mammals, for example, we know that nicotine is an addictive property, so we could make that inference that maybe these neonicotinoids – considering they act on similar targets – may have similar addictive properties.

And our behavioral experiments suggest that that might be the case.”

The study is published in the Britsh journal The Proceedings of the Royal Society B.


[1] Newsweek

[2] ABC News

Neonics Pesticide Replacement Found to be Equally Dangerous to Bees

A chemical touted as a safer replacement for bee-killing neonicotinoid pesticides (neonics) has similar harmful effects, researchers in the U.K. have discovered.

Neonicotinoids are a class of insecticides intended to protect crops from pests by blocking receptors in the insects’ brains, paralyzing and killing them. Even small doses of neonics can cause bees to struggle with navigation, hunting for food, reproduction, and their ability to form new colonies.

As a result of neonics’ effects on pollinators, the European Union (EU) banned the outdoor use of 5 neonicotinoid products in April 2018. Canada began phasing them out on August 15, 2018. However, in the United States, neonics are still widely used.

Due to the development of neonicotinoid resistance among some insects, scientists in recent years have turned to sulfoximine as a replacement. This group of insecticides act on the same class receptors in the insect brain but can safely avoid the enzymes that make some insects resistant to neonics.

Sulfoximine has been approved by regulatory bodies in China, Canada, Australia, and the U.K. [2]

Recently, scientists studied the effects of sulfoxaflor – a member of the sulfoximine class of chemicals – on bumblebee colonies and found that it reduced the number of worker bees in the colony and, eventually, the number of offspring the colony produced.

Study author Harry Siviter, from Royal Holloway, University of London, said:

“Our results show that sulfoxaflor can have a negative impact on the reproductive output of bumblebee colonies under certain conditions.”

Sulfoximine was approved by the U.S. Environmental Protection Agency (EPA) under the Obama Administration. Initially, the rules governing the pesticide’s use were fairly loose, but a court decision vacated the initial approval in favor of more stringent restrictions to protect bees.

It cannot be sprayed on plants that attract bees until they have finished blooming, it is illegal to spray the insecticide on a select number of blooming plants, and it can’t be sprayed on any plants grown for seed.

For the study, researchers exposed bumblebee colonies to doses of sulfoximine similar to those they would be exposed to after the insecticide is applied to crops, and compared their health to those of colonies that were not exposed.

It was clear that the bees had suffered as a result of sulfoximine exposure when individuals from colonies exposed as larvae started to emerge as adults, but fewer worker bees emerged.

Furthermore, 9 weeks after the bumblebees were exposed, exposed colonies produced 54% fewer new queens and males – the only bees that reproduce. The authors wrote in the report that this suggests sulfoximine could significantly impact successful reproduction among bumblebee colonies. [1]

Study author Dr. Ellouise Leadbeater of Royal Holloway, University of London, said:

“Our study highlights that stressors that do not directly kill bees can still have damaging effects further down the line, because the health of the colony depends on the health of its workforce.” [2]

More importantly, the study shows that replacing one toxic insecticide with another is not the answer to protecting crops from pests.

The study is published in the journal Nature.


[1] Science Magazine

[2] EcoWatch