Bee diversity in island-like habitats (kettle holes) to assess connectivity in agricultural landscapes - Part 1 of data collection

During June and July of 2017, wild bees were collected using color traps (blue, yellow and white pans) in small water bodies called kettle holes embedded in agricultural landscapes in the north of Germany. After all wild bees were identified to species level, from a subset of samples we measured the Intertegular distance ITD (distance between the wings) as body size and searched for functional traits regarding sociality (solitary, eusocial, parasitic) nesting type (below- or aboveground), and lecty (poly- or oligolectic). In addition, biotic and abiotic characteristics of these kettle holes were recorded to evaluate how they affect wild bee diversity. These factors included size of the kettle hole, the degree of isolation (number of neighboring kettle holes at different distances), percentage of flowering species and total of plant species (herbs and woody plants). We tested the effect of all these factors on wild bee abundance and bee species richness, as well on body size and functional traits. - Applied Methods for sampling and identification: Collection of individuals using colour traps. One trap had 6 coloured plastic containers (white, blue and yellow) placed in three levels randomly. Water with some drops of soap was added to each container and traps were place in each kettle hole during 48 hours. A total of 4 traps were set up in each kettle hole and a total of 36 kettle holes were studied. After 2 days insects trapped in the water were collected without differentiating the colour of the plastic container. Bee individuals were separated and taken to the lab for further preparation and identification. - Bee specimens were pinned and dried at room temperature. Individuals were identified until species level by specialists K. Rupik from Bielefeld University and C. Saure at the Natural History Museum in Berlin. Information about functional traits regarding sociality, lecty and nesting were compiled from the literature with the final list of species. Body size was characterized as intertegular distance (distance between wings) measured in a subset of randomly selected individuals per species.