Bumblebee brains affected by neonicotinoids
New research has emerged from the Universities of Dundee and St. Andrews which shows that accepted environmental levels of neonicotinoids impair bumblebee brain functionality and consequently negatively impact the performance of whole colonies.
The research, published in the Journal of the Federation of American Societies for Experimental Biology, is the first to demonstrate that the levels of neonicotinoids commonly found in the pollen and nectar of treated plants affect bumblebee brains. The results show that very low levels of neonicotinoids could cause up to a 55% reduction of living bees found in a colony and up to a 71% reduction in healthy brood cells.
On these findings one of the researchers Dr Chris Connolly said: “Our research demonstrates beyond doubt that the level of neonicotinoids generally accepted as the average level present in the wild causes brain dysfunction and colonies to perform poorly when consumed by bumblebees,” he said. “In fact, our research showed that the ability to perturb brain cells can be found at 1/5 to 1/10 of the levels that people think are present in the wild.
“This is not surprising as pesticides are designed to affect brains of insects so it is doing what it is supposed to do but on a bumblebee as well as the pest species. The bumblebees don’t die due to exposure to neonicotinoids but their brains cells don’t perform well as a result and this causes adverse outcomes for individual bees and colonies.
“This is not proof that neonicotinoids are solely responsible for the decline in insect pollinators, but a clear linear relationship is now established. We can now be confident that at these levels, neonicotinoids disrupt brain function, bee learning and the ability to forage for food and so limit colony growth.
“It may be possible to help bees if more food (bee-friendly plants) were available to bees in the countryside and in our gardens. We suggest that the neonicotinoids are no longer used on any bee-friendly garden plants, or on land that is, or will be, used by crops visited by bees or other insect pollinators.”
This latest evidence regarding impaired brain functionality is particularly alarming given that bumblebees rely upon their intelligence to go about their daily tasks, navigating the landscape, locating resources and learning which flowers offer the best rewards and how to access those rewards. It is especially alarming when considered with the other threats bumblebees face such as habitat loss and limited food availability. There is a growing body of evidence showing the harmful effects of neonicotinoids on bumblebees and other animals, and as such the Bumblebee Conservation Trust is advocating for an extension to the current moratorium on neonicotinoid use when it comes to an end in December this year.