BUMBLE BEES ARE IMPORTANT POLLINATORS OF NATIVE AND AGRICULTURAL PLANTS, CONTRIBUTING TO POLLINATION SERVICES WORTH BILLIONS OF DOLLARS ANNUALLY. HOWEVER, MANY BUMBLE BEE POPULATIONS HAVE DECLINED IN RECENT DECADES, WITH VARIOUS FACTORS CONTRIBUTING. ONE RECENTLY RECOGNIZED CONTRIBUTOR IS FUNGICIDE EXPOSURE, WHICH HAS BEEN FOUND TO DECREASE BUMBLE BEE COLONY GROWTH. THE MECHANISM BEHIND THE EFFECTS OF THESE FUNGICIDES IS UNKNOWN, BUT IT IS POSSIBLE THAT THEY DISRUPT BEE-FUNGI RELATIONSHIPS. FUNGI ARE COMMON INHABITANTS OF BEE FOOD STORES, WHERE THEY HAVE BEEN SUGGESTED TO ASSIST IN FOOD BREAKDOWN. THEY ARE ALSO COMMONLY ISOLATED FROM THE GUT OF BEES, THOUGH THEIR FUNCTION THERE IS UNKNOWN. RECENT STUDIES, INCLUDING OUR OWN RESEARCH, FIND THAT BEE-ASSOCIATED FUNGI ARE BENEFICIAL TO BEE HEALTH, AND THAT ASSOCIATION WITH THESE FUNGI REDUCES THE NEGATIVE IMPACTS OF FUNGICIDE EXPOSURE ON BUMBLE BEES. WE PROPOSE PROJECTS TO FURTHER STUDY THE RELATIONSHIPS BETWEEN BEES AND FUNGI, AND THE EFFECTS THAT FUNGICIDES HAVE ON THESE ASSOCIATIONS. OUR SPECIFIC OBJECTIVES ARE TO 1) EXAMINE POTENTIAL MECHANISMS UNDERLYING FUNGAL EFFECTS ON BUMBLE BEES; AND 2) DETERMINE HOW VARIOUS FUNGICIDES IMPACT THE GROWTH OF BEE-ASSOCIATED FUNGI. THIS RESEARCH WILL INFORM CONSERVATION PLANS AND REARING METHODS TO SUPPORT BUMBLE BEE HEALTH AND POLLINATION SERVICES THROUGH APPLICATION OF FUNGI SUPPLEMENTS TO COLONIES AND SELECTION OF FUNGICIDES THAT POSE THE LEAST RISK TO FUNGAL SYMBIONTS.