Bees have been declining by more than 30% throughout the last century. For many years people blamed climate change and so on but it turns out that from Imperial College London’s the Department of Life Sciences Dr. Richard Gill found in a study that pesticides affect the bee’s brain in early stages of life. Which also means if the bee’s brain gets damage then the capability to do its work also suffers. It was also said that if the bee carries the pesticide to its hive then it can damage others as well.
Richard compared that harmful influence on bees as if the human fetus gets damaged when the carrier consume bad substances (for example cigarette smoking or alcohol consumption). A word from Richard: “Worryingly in this case, when young bees are fed on pesticide-contaminated food, this caused parts of the brain to grow less, leading to older adult bees possessing smaller and functionally impaired brains; an effect that appeared to be permanent and irreversible.”
The study had 2 colonies in the lab, one that got fed with pesticide and one with no pesticides. When the bee babies became adults then their learning ability was tested. It showed that those who got fed with pesticides had significantly impaired abilities to learn compared the other half.
Source: https://edition.cnn.com/2020/03/03/world/baby-bees-brains-pesticides-scn/index.html