Assessing Industrial Hemp Pollen (Cannabis sativa L.) for a Protective Effect Against Imidacloprid Exposure in Honey Bees: A Pilot Study

Exposure to sublethal levels of imidacloprid leads to lasting detrimental impacts on honey bees, affecting both individual bees and entire colonies. The main objective of this study was to test the effects of this common insecticide on honey bee Apis mellifera worker's foraging ability and expression of antioxidant genes in the presence of industrial hemp. Industrial hemp, Cannabis sativa L., contains a range of phytocannabinoids that can activate the antioxidant system in the hemolymph of the adult honey bee. As a result, it may have the potential to counteract the harmful effects of neonicotinoids. This may improve survival and pesticide tolerance in honey bees. Hemp pollen was manually collected from John C. Horticultural Center in Haysville, KS, through the Kansas State University Industrial Hemp Program. 5 colonies were exposed to one of five treatments: control (no patty, untreated sugar water), hemp pollen patty only, commercial pollen patty only, hemp pollen patty + imidacloprid (20ppb), or commercial pollen patty + imidacloprid (20ppb) for 4 weeks. We found that bees given hemp pollen plus imidacloprid showed significantly higher forager numbers and pollen collection than those given commercial pollen patty along with imidacloprid. We also saw an upregulation of three genes in the antioxidant/detoxification pathway in the abdomen for foragers in bees fed hemp pollen indicating increased activation of this pathway to combat insecticide exposure. This suggests that supplementation of honey bee diet with hemp pollen may be beneficial for pesticide stress.