1. Division of Forest Entomology, Swedish University of Agricultural Sciences, S‐750 07 Uppsala, Sweden;
2. Zoology Department, Tromsø Museum, University of Tromsø, N‐9037 Tromsø, Norway;
3. Abisko Scientific Research Station, S‐981 07 Abisko, Sweden;
4. Department of Ecology, Institute of Biology, University of Tromsø, N‐9037 Tromsø, Norway