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Native plants attractive to beneficial insects may improve the value of buffer strips by contributing to local biodiversity and enhancing the delivery of insect-derived ecosystem services. To determine best management practices for designing buffer strips that conserve beneficial insects, nine plant communities were evaluated. We hypothesized that the diversity and abundance of beneficial insects will be: (1) greatest in diverse plant communities with continuous availability of floral resources; (2) intermediate in plant communities with reduced plant species richness and availability of floral resources; and, (3) lowest in plant communities composed of a single species. More diverse and abundant beneficial insect communities were observed in diverse and forb-only plant communities compared to simple plant communities, especially in treatments composed of species attractive to beneficial insects compared to compositions recommended for prairie restoration. Model comparisons revealed significant positive relationships between the diversity and abundance of beneficial guilds with plant

Native plants attractive to beneficial insects may improve the value of buffer strips by increasing biodiversity and enhancing the delivery of insect-derived ecosystem services. In a 2-yr field experiment, we measured the response of insect communities across nine buffers that varied in plant diversity. We constructed buffers with plants commonly found in buffers of USDA-certified organic farms in Iowa (typically a single species), recommended for prairie reconstruction, or recommended for attracting beneficial insects. We hypothesized that the diversity and abundance of beneficial insects will be 1) greatest in buffers composed of diverse plant communities with continuous availability of floral resources, 2) intermediate in buffers with reduced species richness and availability of floral resources, and 3) lowest in buffers composed of a single species. We observed a significant positive relationship between the diversity and abundance of beneficial insects with plant community diversity and the number of flowers. More beneficial insects were collected in buffers composed of species selected for their attractiveness to beneficial insects than a community recommended for prairie restoration. These differences suggest 1) plant communities that dominate existing buffers are not optimal for attracting beneficial insects, 2) adding flowering perennial species could improve buffers as habitat for beneficial insects, 3) buffers can be optimized by intentionally combining the most attractive native species even at modest levels of plant diversity, and 4) plant communities recommended for prairie reconstruction may not contain the optimal species or density of the most attractive species necessary to support beneficial insects from multiple guilds.