Pan traps
Pan traps were installed for four time periods (June 28th-July 1st, July 5th-8th, July 12th-15th, July 23rd-26th) as an indirect measure of abundance (Scherber & Beduschi 2021) to assess insects on plots containing wheat, faba bean, linseed and oilseed rape, their mixtures and plots with no crop sown. We had to exclude the third round, because heavy rain flooded the traps. We used plastic bowls sprayed with UV yellow paint (MONTANA BLACK INFRA COLORS infra yellow), filled with water and a drop of detergent (Frosch). Traps were placed at ground level in the vegetation of each plot and were left active for 72 h; then we transferred insects into 70% ethanol in the field and sorted them up to order/suborder level in the laboratory using binoculars (Leica EZ4-HD). We summed individuals from all three sampling periods per crop diversity (four levels) and per crop mixture (13 levels, Table S12).