Pesticides applied to honeybee hives to kill Varroa mites and other parasites may actually be hurting the bees by damaging bacteria in their guts, according to a study published in the journal Frontiers in Microbiology.
Varroa mites, along with the class of insecticides known as neonicotinoids, are considered the leading culprits in the decline of honeybee populations.
“Although helpful for ridding hives of parasites and pathogens, the chemicals in beekeeper-applied pesticides can be harmful to the bees,” said Mark Williams, an associate professor of horticulture Virginia Tech and the study’s lead author, in a release.
The study found that the application of three different pesticides “can affect the gut’s ability to metabolize sugars and peptides, processes that are vital for honeybee health.” Williams said that “honeybees from chlorothalanil-treated hives showed the greatest change in gut microbiome.”