Bumblebees are becoming increasingly addicted to pesticides

The inclusion of pesticides causes addictive behavior in bumblebees

The increased use of pesticides is known to cause all sorts of problems. Researchers have now discovered that bumblebees develop certain symptoms of addictive behavior after ingesting pesticide-contaminated food.

Researchers at Imperial College London and Queen Mary University of London (QMUL) found in their current research that bumblebees develop addictive behavior through exposure to pesticides. The physicians published the results of their study in the English-language journal "Proceedings of the Royal Society B".

Pesticides affect the reproductive success of bumblebees

Investigating the behavior of bumblebees showed that the risk of pesticide-contaminated food reaching bumblebee populations is higher than previously thought, which can significantly affect the reproductive success of the colony. Bumblebees get used to the taste of so-called neonicotinoids and even develop a kind of addictive behavior. As a result, bumblebee colonies are increasingly feeding on pesticide food over time.

Which pesticides have been studied?

The researchers investigated a controversial class of pesticides called neonicotinoids, which are currently among the most widely used pesticides in the world, even though these pesticides are almost completely banned in the EU. The effects of neonicotinoids on bees have been a hot topic for some time now.

Bees may develop a preference for pesticide-contaminated food

When bumblebees or bees have a choice, they often avoid foods that are often treated with neonicotinoids. However, when individual bees increasingly consume contaminated food, they eventually develop a preference for this form of food, study author Dr. Richard Gill of the Department of Life Sciences at Imperial College London in a press release on the study results.

Symptoms of addictive behavior are similar to those of nicotine

Interestingly, neonicotinoids target nerve receptors in insects that resemble receptors that are targeted by nicotine in mammals. The findings are fascinating for experts: If bumblebees have a preference for neonicotinoids and thereby even develop certain symptoms of addictive behavior. This is comparable to the addictive properties of nicotine in humans. More research is now needed to further investigate the effects, the researchers emphasize.

Ten colonies of bumblebees were studied in the study

The researchers studied ten colonies of bumblebees over a period of ten days. Each colony had access to food which either contained neonicotinoids or was free of pesticides. In the beginning, bees preferred pesticide-free food. Over time, more and more of the insects fed on food with pesticides. Pesticide-free food was consumed continuously less. The bees continued to favor pesticide-fortified food, even when the feed trough positions were changed, suggesting they could detect the pesticide in the feed. Further investigations are now to clarify the mechanism why the insects develop this preference.

Additional research is needed

Many studies on neonicotinoids feed bees exclusively on pesticide-laden foods, but in actual fact, wild bees have a choice of where to get their food, study author Dr. Andres Arce from Imperial College London. Scientists now need to find out if bees can recognize the pesticides and how they can learn to avoid such contaminated food and feed on non-contaminated food. For at first, the bumblebees shunned the pesticide-containing foods and only increased their intake of pesticides over time. (As)