Honey bee-collected pollen richness and protein content across an agricultural land-use gradient

Abstract

Higher protein content and greater taxonomic richness of pollen have been noted as beneficial for bee health, but the relationship between pollen protein content and richness as well as how pollen protein content varies across landscape gradients remain understudied. We assessed correlations between pollen protein content and plant species richness and species composition in pollen collected from honey bee colonies across three states over 2 years. We selected sites along an agricultural-grassland gradient to investigate how pollen protein content and species composition varied with land-use. We observed a weak, negative relationship between pollen protein content and taxonomic richness, although we found no evidence of relationships between land-use and either pollen richness or species composition. Results suggest that the richness of pollen collected by honey bees can, albeit weakly, correlate with the pollen protein content in agroecosystems of the Upper Midwest, and that in some systems, land use may have minimal influence on the species collected by honey bees.