D3492: Snapshot of foraging behavior of Apis mellifera through pollen metagenomics

The domesticated honeybee (Apis millifera) plays a large role in pollination of plants in the southeastern United States. Each foraging honeybee collects pollen which is an edible source of protein, nutrients and plays a role in honeybee larval development. DNA extracted from collected pollen provides a unique snapshot of honeybee foraging behavior and plant biodiversity. Few studies have used DNA and metagenomics to assess honeybee plant usage geographically and temporally. In our study we collected pollen directly from bees in apiaries from our school campus and a nearby farm, both located in suburban city environments. Our hypothesis was that honeybees at the farm apiary would collect pollen from flowering farm plants in contrast with campus honeybees which would forage from available flowering plants in the surrounding suburban landscape. We found that farm honeybees largely ignored farm plants, and that honeybees at both locations used similar families of plants during the foraging year. In most months of the foraging season, one or two plants dominated foraging behavior at both locations, and in some months 90% of the pollen foraged came from one plant species. We suggest that honeybee foraging in spring and summer is based on plant abundance and not plant diversity. In contrast, in late fall months plant diversity increases as bees adjust to forage on those plants still blooming.  The use of pollen as a DNA source for metagenomic sequencing provides unique insight to honeybee plant utilization at geographic and temporal scales.