Microhymenoptera in roadside verges and the potential of arthropod-friendly mowing for their preservation

This dataset contains data from the paper: “Haas-Renninger, M., Weber, J., Felske, I., Kimmich, T., Csader, M., Betz, O., Krogmann, L., Steidle, J. L.M. 2023. Parasitoid Hymenoptera in roadside verges and the potential of insect-friendly mowing for their preservation. Journal of Applied Entomology.”

The study investigates which families of parasitoid Hymenoptera occur in roadside grassland and might suffer from mowing with a conventional mowing head ("MK1200" from MULAG), which parasitoid families benefit from insect-friendly mowing using an “insect-friendly” mowing head ("Eco 1200 plus" from MULAG), and which parasitoid families benefit from the use of a flushing bar attached to the mowing head.

We found specimens of 18 families from the six parasitoid superfamilies Chalcidoidea, Ceraphronoidea, Diaprioidea, Ichneumonoidea, Platygastroidea, and Proctotrupoidea. Mowing with a conventional mulching mower caused a significant loss of up to 64 % for parasitoid Hymenoptera. The Eco 1200 plus showed an insect-friendly effect only on the number of individuals of Chalcidoidea, saving 38 % of individuals compared to the conventional mower. The flushing bar showed a significant effect on total number of individuals with a reduction only on Chalcidoidea and a tendency for Ichneumonoidea with 30 % and 47 %, respectively.

This study shows that mowing with a conventional mulching mower has detrimental effects on parasitoid Hymenoptera and that this effect can be partly reversed through the insect-friendly mower and a flushing bar.

Methods
For the first experiment, Hymenoptera samples from "Steidle, J. L.M., Kimmich, T., Csader, M. Betz, O. 2022. Negative impact of roadside mowing on arthropod fauna and its reduction with “arthropod-friendly” mowing technique. Journal of Applied Entomology" were reanalyzed. Here, plots were either not mown, or mown with the a standard mowing head "MK1200", or the mowing head "Eco 1200 plus" (both from the company MULAG, Germany).

In the second experiment, plots were either not treated or treated with a flushing bar without mowing head.

In both experiments, Arthropods were sampled in the plots using biocoenometers and an insect vacuum cleaner, and Hymenoptera were determinded up to family level.