Stress is causing bee colonies to fail. Bees experience high levels of stress when exposed to pesticides, preventing colonies from functioning properly, according to a study conducted by UK scientists.

Scientists from the Royal Holloway University said that even low levels of neonicotinoid pesticides influence their behavior, causing them to stop working properly for their colonies.

They stated that the pesticide is not directly fatal. As it is a neuroactive chemical, it affects the mental state of the bees. They become stressed by the presence of the pesticide, which eventually hinders their capability to properly maintain their hives, thus resulting in failure of many bee colonies, Motherboard reports.

"One in three mouthfuls of our food depend on bee pollination," lead author, Dr John Bryden from the School of Biological Sciences at Royal Holloway, said in an official statement. "By understanding the complex way in which colonies fail and die, we've made a crucial step in being able to link bee declines to pesticides and other factors, such as habitat loss and disease which can all contribute to colony failure."

"Exposing bees to pesticides is a bit like adding more and more weight on someone's shoulders. A person can keep walking normally under a bit of weight, but when it gets too much - they collapse. Similarly, bee colonies can keep growing when bees aren't too stressed, but if stress levels get too high the colony will eventually fail," said Bryden.

According to Wired, last winter, nearly a third of commercial bee colonies in the United States collapsed. The rapid loss of bee colonies, globally, also known as colony collapse disorder (CCD), will have serious repercussions on food production worldwide.

"Our research provides important insights to the biology of pollinators," said co-author Professor Vincent Jansen. "It is intriguing that the way in which bees work together is the key to their success, but could also contribute to their decline and colony failure."

"Pesticides can have a detrimental effect on bees at levels used in the field," said co-author Dr Nigel Raine. "Our research will provide important evidence for policymakers. The way we test pesticides, the way we assess their impact on bees, and the way we manage pesticides can all be improved."