Planting native perennials to attract pollinators in East Tennessee

Native perennial plantings provide essential pollen and nectar resources for pollinator conservation. To determine the relative attractiveness of native plants to their insect visitors in eastern Tennessee, we planted four replicate sets of pollinator plots in sites differing in landscape composition. We quantified pollinator visitation rates to flowers of three plant families.
We chose five landscapes: urban, semi-natural, forage grassland, organic agriculture, and mixed-use agriculture. In each landscape, we established four plots, representing species of the Asteraceae, Fabaceae, or Lamiaceae and one “Mixed” plot comprising species of each family. Each plot contained six native perennial species with four individuals per species. We collected insects that touched the reproductive parts of flowers with an insect-vacuum for 5-minutes per flower species, per plot. We repeated these collections at each site throughout the flowering season.
In 2019, we collected a total of 1,652 insects in 26.3 hours. Overall, we found little variation in insect abundance across landscapes, despite observed plant species preference. We repeated the study in 2020 and found plants in their second year of growth had a larger floral display. To date in 2020, we have collected over 3,000 specimens over 72 sampling hours. We observed the highest visitation rates on species of the Lamiacae family and at the mixed-use agriculture site, but family level visitation rates were site-dependent.
We can use this study to expand our understanding foraging preferences of pollinators across landscapes in East Tennessee and to share our findings with stakeholders interested in pollinator conservation.