PRODUCTION OF MANY CROP PLANTS REMAINS DEPENDENT ON INSECT POLLINATION, WHICH OCCURS AS A RESULT OF INSECT ATTRACTION TO THE NECTAR AND POLLEN OF FLOWERS. RECENT ADVANCES IN POLLINATION BIOLOGY HAVE DEMONSTRATED THAT NECTAR TRAITS ARE FREQUENTLY ALTERED BY NECTAR-INHABITING MICROBES (BACTERIA AND YEAST), LEADING TO CHANGES IN BEE VISITATION RATES. DESPITE THE CENTRAL ROLE OF NECTAR TRAITS IN CROP POLLINATION THERE IS LIMITED INFORMATION ON NECTAR TRAITS THAT HAVE KNOWN EFFECTS ON BEE PREFERENCE. THE GOAL OF THIS PROJECT IS TO EXPLORE THE INTERACTION AMONG SUNFLOWERS, NECTAR-INHABITING MICROBES, AND BEES IN DETERMINING SUNFLOWER POLLINATION SUCCESS. THIS WILL BE ACCOMPLISHED THROUGH 3 OBJECTIVES: 1) CHARACTERIZE SUNFLOWER NECTAR TRAITS AND NECTAR-INHABITING MICROBES USING A COMPARATIVE FIELD STUDY 2) ASSAY BEE PREFERENCE FOR MICROBIALLY INOCULATED NECTAR IN A LAB STUDY AND 3) MEASURE CHANGE IN SUNFLOWER NECTAR TRAITS AND BEE VISITATION FOLLOWING MICROBIAL INOCULATION IN AN EXPERIMENTAL FIELD STUDY. THE RESULTS OF THIS PROJECT WILL REDUCE THE COST OF SUNFLOWER PRODUCTION BY TESTING NEW MANAGMENT STRATEGIES INVOLVING THE INTRODUCTION OF BENEFICIAL NECTAR MICROBES.