1. Department of Ecology, Environment and Plant Sciences; Stockholm University; Stockholm Sweden
2. Department of Agricultural Sciences; University of Helsinki; Helsinki Finland
3. Ecological Sciences, The James Hutton Institute; Dundee U.K.
4. Metapopulation Research Centre, Department of Biosciences; University of Helsinki; Helsinki Finland
5. Department of Plant Protection Biology; Swedish University of Agricultural Sciences; Alnarp Sweden
6. Department of Food and Environmental Sciences; University of Helsinki; Helsinki Finland
7. Department of Entomology; Cornell University; Ithaca New York U.S.A