VALUED AT ~$20 BILLION ANNUALLY IN U.S. AGRICULTURE, MANAGED POLLINATION DELIVERY BY APIS MELLIFERA, THE WESTERN HONEY BEE, IS THREATENED BY UNSUSTAINABLE ANNUAL LOSSES ASSOCIATED WITH PESTICIDE EXPOSURE AND SUBOPTIMAL NUTRITION DUE TO REDUCED FLORAL DIVERSITY. LIKE HONEY PHYTOCHEMICALS, PHYTOCHEMICALS OF BEEBREAD, PRINCIPAL PROTEIN SOURCE FOR NURSE AND LARVAL BEES, MAY HAVE FUNCTIONAL SIGNIFICANCE IN PROTECTING BEES AGAINST PATHOGENS AND TOXINS AND IN REGULATING DEVELOPMENT. BECAUSE YEASTS AND OTHER FUNGI, UBIQUITOUS COMPONENTS OF THE BEEBREAD "MYCOBIOME", MAY CONTRIBUTE TO CONVERTING POLLEN TO BEEBREAD, BEYOND THEIR DIRECT EFFECTS, FUNGICIDE EXPOSURE MAY COMPROMISE BEE HEALTH INDIRECTLY BY REDUCING FOOD QUALITY. THUS, THE OBJECTIVES OF THIS PROJECT ARE TO: 1) CHARACTERIZE THE BEEBREAD MYCOBIOME (USING CULTURE-INDEPENDENT NEXT-GENERATION SEQUENCING); 2) DETERMINE WHETHER ASPERGILLUS FLAVUS BB, AN ACID-TOLERANT, OSMOPHILIC BEEBREAD ISOLATE, REPRESENTS A SYMBIOTIC VARIANT ADAPTED TO COEXIST WITH HONEY BEES; 3) QUANTIFY PHYTOCHEMICAL DIFFERENCES BETWEEN POLLEN, FRESH BEEBREAD, AND POST-PROCESSING BEEBREAD, TO ASCERTAIN THE EXTENT TO WHICH CONVERSION CHANGES TOXIN CONTENT; 4) EVALUATE FUNCTIONAL DIFFERENCES BETWEEN POLLEN, FRESH BEEBREAD AND POST-PROCESSING BEEBREAD (E.G., EXPRESSION LEVELS OF IMMUNITY AND DETOXIFICATION GENES, DIET-RELATED HYPOPHARYNGEAL GLAND STRUCTURE AND NURSING BEHAVIOR); AND 5) DETERMINE THE EFFECTS OF FUNGICIDE CONTAMINATION ON BEEBREAD FUNCTIONAL CHARACTERISTICS. THIS PROJECT WILL GENERATE NEW KNOWLEDGE OF BEEBREAD PRODUCTION, FUNCTIONALITY, AND RESPONSES TO FUNGICIDES IN ORDER TO CLARIFY THE ROLE OF THE HONEY BEE MYCOBIOME IN PROMOTING THE HEALTH AND SUSTAINABILITY OF THIS ESSENTIAL MANAGED POLLINATOR.