Two new studies published in Nature on Wednesday show that neonicotinoid pesticides—or neonics for short—may be even more harmful to bees than previously thought.
Those studies, Bees Prefer Foods Containing Neonicotinoid Pesticides and Ecology: Tasteless Pesticides Affect Bees in the Field, add to the growing list of evidence that neonics are a major contributing factor to bee population decline and reinforce the case for restricting the use of those pesticides.
In the first study, researchers from Newcastle University conducted a test to determine how honeybees and bumblebees responded to nectar laced with three of the most commonly used neonics, and found that both species actually preferred those solutions. The data also indicated that the bees preferred the pesticides—imidacloprid (IMD), thiamethoxam (TMX), and clothianidin (CLO)—even though they could not taste them and the consumption of the pesticides caused the bees to eat less overall.
“Like nicotine they are essentially amplifying the rewarding properties of the sucrose solution that they are located in and the bees think its more rewarding so they go back to that food tube to drink more of it,” Professor Geraldine Wright, who led Newcastle University’s study, told the Guardian on Wednesday.
It was unclear if that preference would remain in the wild. However, the researchers note, “Sublethal concentrations alter the behavior of social bees and reduce survival of entire colonies… This work shows that bees cannot control their exposure to neonicotinoids in food and implies that treating flowering crops with IMD and TMX presents a sizeable hazard to foraging bees.”
“At this point in time it is no longer credible to argue that agricultural use of neonicotinoids does not harm wild bees.”