Timing and mulching frequency affected the number of nests of cavity-nesting wasps that hunt for aphids in forest meadows

Abstract Mulching, cutting of the vegetation without plant biomass removal, is a common alternative to mowing. The aim our study was find out if mulching forest meadows at different time points affects cavity-nesting bees and wasps. We exposed trap nests for wasps 24 in south-western Germany over 2 years applied four experimental treatments with six replicates: (i) June, (ii) September, (iii) June (iv) no as control. Nests were collected throughout growing period. insects sorted analyzed according functional groups. Mulching September reduced nest number all second but not first year. separation into three groups (bees, herbivore-hunting carnivore-hunting wasps) showed that wasp by both Specifically, aphid-hunting influenced or twice Aphid-hunting likely their larval food meadows, while other studied main surrounding forests are therefore negatively affected. Implications insect conservation For maintaining reproductive success hunt aphids, we recommend once rather than