POLLINATION OF APPROXIMATELY 75% CROPS WORLDWIDE DEPENDS ON INSECT POLLINATORS PROVIDED MOSTLY BY WILD AND MANAGED BEES. HOWEVER, MANY BEE SPECIES ARE EXPERIENCING DECLINES ATTRIBUTED TO HABITAT LOSS, DECREASED FLORAL RESOURCES, AND INCREASED PATHOGEN PREVALENCE. IN TEMPERATE REGIONS, THESE STRESSORS ARE EXACERBATED DURING THE WINTER-DIAPAUSE, A CRITICAL PHASE DURING THE LIFECYCLE OF MANY ANNUAL BEE SPECIES, INCLUDING SOLITARY GROUND-, CAVITY-, AND SOCIAL NESTING BEES.DURING DIAPAUSE, BEES COPE WITH ADVERSE CONDITIONS SUCH AS COLD-STRESS AND STARVATION, AND MUST MAINTAIN SUFFICIENT NUTRIENT RESERVES FOR SPRINGTIME NEST FOUNDATION. THESE CHALLENGES MAY RESULT IN SUBSTANTIAL MORTALITY AND POPULATION DECLINES AND CAN BE PARTICULARLY DAMAGING FOR SOCIAL SPECIES (E.G., BUMBLE BEES) WHERE A SINGLE QUEEN PRODUCES MULTIPLE FUTURE QUEENS FOLLOWING A WINTER-DIAPAUSE. DESPITE THE CRITICAL ROLE OF DIAPAUSE FOR SPECIES SURVIVAL, OUR KNOWLEDGE OF THE PHYSIOLOGY ASSOCIATED WITH DIAPAUSE SURVIVAL AND PERFORMANCE IN BEES IS STILL LIMITED. HERE, I WILL USE BUMBLE BEES AS A MODEL SYSTEM TO EXAMINE PHYSIOLOGICAL FACTORS THAT AFFECT DIAPAUSE SURVIVAL AND POST-DIAPAUSE REPRODUCTIVE PERFORMANCE IN ANNUAL BEES.I WILL EXAMINE HOW DIAPAUSE SURVIVAL IS AFFECTED BY QUEENS' AGE AND BODY MASS DURING EARLY-LIFE, AND HOW THESE FACTORS INFLUENCE COLD TOLERANCE, NUTRIENT ACQUISITION AND STRESS TOLERANCE IN BOTH LAB AND FIELD SETTINGS. THIS PROJECT WILL IMPROVE CONSERVATION OF ANNUAL BEES BY PROVIDING RECOMMENDATIONS FOR FLORAL PROVISIONING THAT WILL SUPPORT WILD BEES, AND INCREASE PRODUCTIVITY OF COMMERCIALLY MANAGED BUMBLE BEES.