Intensive forestry is a threat to biodiversity, and therefore actions are made to mitigate this loss. The actions are, however, designed based on available knowledge about the requirements of species, and for saproxylic insects this concerns mainly Coleoptera, while the diverse but poorly known Hymenoptera has contributed less. In this paper we therefore asked whether the substrate requirements of Hymenoptera (divided as parasitoids and non-parasitoids) are similar to those of Coleoptera and Diptera. We used an insect material reared from logging residue wood for the comparison. Theoretically parasitoid Hyme- noptera should be less specialised than Coleoptera and other host species as they belong to a higher trophic level. However, we found no such difference and even an opposite trend, that parasitoids were more specialised than beetles. Parasitoids had significantly more species in newly dead wood of fine diameter (1–4 cm, compared to coarse wood of 8–15 cm) compared to other groups. This is probably due to that many of them have bark beetles as hosts. The non-parasitoids were less specialised than the other groups and more confined to old wood (4–5 years), which is in line with that many of them are aculeate wasps building nests in emergence holes from other insects.

Implications for insect conservation The habitat requirements of Hymenoptera suggest that the conservation actions designed for the well known groups are also applicable for them. The parasitoids’ association to trivial substrates (fine wood) sug- gest a good supply of breeding habitat, whereas their high specialisation in combination with higher trophic level suggest they contain an even higher proportion of threatened species than Coleoptera. How this is traded off needs further studies.