A joint Emory University and University of Washington study published in Proceedings of the Royal Society B indicates that streptomycin, an antibiotic sprayed on orchard crops to combat bacterial diseases, slows the cognition of bumblebees and reduces their foraging efficiency. Laura Avila, first author of the paper and a postdoctoral fellow in the Emory Department of Biology, states, “No one has examined the potential impacts on pollinators of broadcast spraying of antibiotics in agriculture despite their widespread use.”

The researchers think that the negative impact of streptomycin on bumblebees may be due to the disruption of the insects’ microbiome. In lab experiments with managed bumblebees (Bombus impatiens) to test the effects of an upper-limit dietary exposure to streptomycin, half of the bees were fed sugar water to simulate nectar. The remaining bees were fed sucrose dosed with streptomycin. After two days on this diet, the bees fed streptomycin displayed a marked decrease in short-term memory and foraging ability. The scientists note the timing of antibiotic application, the amount applied and possible alternatives to the use of an antibiotic may be potential mitigation methods if research verifies the harmful impacts on bumblebees of agricultural spraying with streptomycin.