The overarching goal of this project is to characterize the impact of antibiotic applications to pear orchards on the microbiomes--communities of symbiotic bacteria living within animals--and the foraging behavior of bee pollinators.Objective 1. Measure the extent to which bees are exposed to antibiotics in pear orchards, and their associated impact on colony-level gut microbiome composition, individual and colony foraging in the field.1.1. Quantify antibiotic traces (streptomycin and oxytetracycline) in floral and bee pollen.1.2. Track changes in bee microbiome composition (taxonomic abundance and diversity; prevalence of antibiotic-resistant genes).1.3. Measure changes in individual (bumble bees and honey bees) & colony-level (bumble bees) foraging.Objective 2. Test if microbiome changes alone can drive individual changes in bee learning, memory, and foraging, in the laboratory.2.1. Measure whether the main driver of changes in individual learning and memory is the indirect impact of antibiotics on the bee gut microbiome, as opposed to direct antibiotic neurotoxicity.2.2. Measure whether the main driver of changes in individual foraging is the indirect impact of antibiotics on the bee gut microbiome, as opposed to direct antibiotic neurotoxicity.