1. National Centre for Biosystematics, Natural History Museum, University of Oslo, Post Office Box 1172 Blindern, NO-0318 Oslo, Norway.
2. Tromsø University Museum, University of Tromsø, NO-9037 Tromsø, Norway.
3. Norwegian University of Life Sciences, Post Office Box 5003, NO-1432Ås, Norway.
4. Laboratoire d'Ecologie Alpine, CNRS UMR 5553, Université Joseph Fourier, Post Office Box 53, F-38041 Grenoble Cedex 09, France.