**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** CLIMATE CHANGE IS A PRIMARY DRIVER OF BEE DECLINES, AND HEATWAVES IN PARTICULAR ARE PROJECTED TO INCREASE IN FREQUENCY AND MAGNITUDE ACROSS THE UNITED STATES. WE HAVE A LIMITED UNDERSTANDING OF THE IMPACTS OF HEATWAVES ON BEE SURVIVAL, DEVELOPMENT, AND FITNESS. THIS INFORMATION IS CRITICAL FOR GUIDING INFORMED MANAGEMENT DECISIONS AND PREDICTING FUTURE IMPACTS TO POPULATIONS AND POLLINATION SERVICES FOR AGRICULTURE. MY PROJECT WILL QUANTIFY THE IMPACTS OF HEATWAVES ON AN IMPORTANT, MANAGED CROP POLLINATOR--THE BLUE ORCHARD BEE, OSMIA LIGNARIA. I WILL INVESTIGATE THE IMPACTS OF HEATWAVES ON TWO KEY STAGES OF EARLY DEVELOPMENT ACROSS THREE WESTERN POPULATIONS USED FOR CROP POLLINATION. I COMBINE GREENHOUSE AND LABORATORY EXPERIMENTS TO (1) DETERMINE THE IMPACTS OF HEATWAVES ON ORGANISMAL RESPONSES, SUCH AS DEVELOPMENT AND SURVIVAL, AND (2) IDENTIFY MOLECULAR MECHANISMS ASSOCIATED WITH HEAT STRESS AND RESILIENCE. THIS RESEARCH IMPROVES OUR UNDERSTANDING OF WHEN (WITH RESPECT TO LIFE CYCLES), WHERE (WITH RESPECT TO GEOGRAPHIC VARIATION), AND HOW (AT THE ORGANISMAL AND MOLECULAR LEVELS) HEATWAVES IMPACT ORCHARD BEES. THIS SUPPORTS SUSTAINED POLLINATION SERVICES TO AGRICULTURE AND ENABLES FARMERS AND OTHER STAKEHOLDERS TO PLAN FOR WORSENING CLIMATE EVENTS.