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).