HONEY BEES AND BUMBLE BEES ARE AGRICULTURALLY IMPORTANT INSECTS THAT POLLINATE MORE THAN $15 BILLION OF CROPS IN THE UNITED STATES ALONE EACH YEAR. HOWEVER, WHILE PRODUCTION OF BEE-POLLINATED CROPS HAS STEADILY INCREASED OVER THE LAST CENTURY, BOTH HONEY BEE AND BUMBLE BEE POPULATIONS HAVE SUFFERED DRAMATIC DECLINES. THE CAUSE OF THIS PHENOMENON--COMMONLY REFERRED TO AS 'COLONY COLLAPSE DISORDER' IN HONEY BEES-- REMAINS UNKNOWN, ALTHOUGH SEVERAL STRESS FACTORS ARE THOUGHT TO CONTRIBUTE TO BEE MORTALITY, INCLUDING EXPOSURE TO PATHOGENS AND IMMUNE DEFICIENCY. BEES HARBOR SPECIALIZED GUT MICROBIAL COMMUNITIES (OR GUT MICROBIOTA) THAT ARE ESSENTIAL FOR THEIR HEALTH. WHILE NORMAL GUT MICROBIOTA ASSISTS WITH DIGESTION, ABSORPTION OF NUTRIENTS, AND DEFENSE AGAINST PATHOGENS, DYSBIOSIS (OR PERTURBATION) OF GUT MICROBIOTA IS ASSOCIATED WITH DISEASE. THUS, A RESEARCH GOAL OF HIGH PRIORITY IN THE AGRICULTURAL SCIENCES IS TO IDENTIFY THE MECHANISMS UNDERLYING HOW A HEALTHY COMMUNITY IS ESTABLISHED IN THE BEE GUT. THIS PROJECT WILL ELUCIDATE HOW THE BEE INNATE IMMUNE SYSTEM IMPACTS THE ASSEMBLY AND STABILITY OF SPECIALIZED GUT MICROBIOTA THAT BENEFIT BEE HEALTH. RESULTS WILL IMPROVE OUR UNDERSTANDING OF HOW GUT MICROBIOTA IMPACT BEE IMMUNE FUNCTION AND PROVIDE NOVEL INSIGHTS FOR MANIPULATING BEE GUT MICROBIOTA TO IMPROVE COLONY HEALTH.