1. Organismal and Evolutionary Biology Research Programme University of Helsinki Helsinki Finland
2. Department of Biology Lund University Lund SE‐223 62 Sweden
3. Centre for Biodiversity Dynamics Department of Biology Norwegian University of Science and Technology Trondheim N‐7491 Norway
4. Helsinki Institute of Life Science University of Helsinki Helsinki Finland
5. Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich CH‐8057 Switzerland
6. Department of Ecology and Evolutionary Biology Cornell University Ithaca New York 14853 USA