Ecology of urban bees: preference for native plants in the green spaces of Quito

Abstract

Across the Andes, bee diversity remains poorly documented, particularly in urban environments. At the same time, South American cities are characterized by highly modified plant communities in which native and exotic species coexist, providing an opportunity to evaluate how urban vegetation influences native pollinator communities. We combined citizen science records (iNaturalist), museum collections, and standardized field observations to characterize bee diversity, spatial distribution, and floral associations across the city of Quito, Ecuador. We quantified bee visitation to five native and three exotic plant species over a four-month period, although only six species flowered sufficiently to be included in the analyses. In total, we identified 31 bee morphospecies belonging to five families, of which only one species (Apis mellifera) was exotic. Excluding A. mellifera, all native bee families showed a clear preference for native flowering plants, although most species were polylectic and also visited exotic flowers when preferred resources were unavailable. Native plant richness and abundance were the strongest predictors of native bee diversity, and Dalea coerulea, Bidens andicola, and Lupinus pubescens emerged as the most important floral resources for urban pollinators. Our findings demonstrate that native flowering plants play a central role in sustaining bee diversity within Andean cities and highlight the value of integrating native vegetation into urban green spaces to strengthen pollinator conservation and ecosystem functioning.