Flower selection of Xylocopa violacea: aromatic and ornamental plants as resources in a botanic garden

We assessed the interactions between aromatic and ornamentals plants and local pollinators in a botanic garden. We focused our attention on a frequent solitary bee, Xylocopa violacea, that thanks to its large size and its feeding preferences can visit many types of flowers. By conducting linear walking transects, we recorded all flower visits by bees, highlighting those of X. violacea. We analysed bee preferences in terms of plant family, plant origin or flower morphology. We also identified plant species that were visited by X. violacea together with other foraging bees. Results indicated that X. violacea selectively visits flowering plant species at the botanic garden, preferring Lamiaceae and bilabiate flower types on which legitimate or illegitimate visits can be performed. Other bee species do concurrently visit the same plants, and in the future studies on competition, resource exploitation and pollination success will be addressed.