Evaluation of impact of agriculturally applied antibiotics to pollinator health

On apple trees, streptomycin is applied to open flowers 2-3 times annually at the rate of 0.7 lb per acre to control fire blight (Erwinia amylovora). Application of these antibiotics often overlaps the flowering period of such crops and thus may have unintended adverse health effects on pollinators. There is a big knowledge gap regarding whether streptomycin applied to apple trees against fire blight is transferred to pollinating insects when they visit the treated flowers, and to what extent do the antibiotics affect their gut microbiome and health. The impact of antibiotics to pollinator health has been previously evaluated through a direct feeding of oxytetracycline to honey bees. The structure and diversity of the gut microbiome in bumble bees has been shown to play important roles in bee health. We identified several knowledge gaps in this area: 1. whether the residual concentration of agriculturally applied antibiotics to control plant pathogens would be potent enough to induce microbiome shift in bee gut, 2. whether the microbiome alteration would cause adverse impact to the bee health, 3. if microbiome is shifted upon antibiotic exposure, whether and how soon it is be restored after disturbance when antibiotics exposure is no longer there.