Original data comes from a project which takes or took place as part of the DFG priority program "Exploratories for large-scale and long-term functional biodiversity research". The data is stored together with descriptive metadata, in combination called a dataset, in the project repository (https://www.bexis.uni-jena.de). Species information was extracted from that original dataset. The second paragraph is part of the metadata of the original dataset. Specialisation of flower visitors is compared across grasslands along a gradient of land use intensity. We focus on resource-based mechanisms that may determine flower visiting insect communities in different habitats. We analyze flower visiting rates of pollinators in order to measure possible variation between differently used sites. Moreover, we characterize the degree of specialisation on species and community level (pollinator networks; Blüthgen et al. 2007).