1. Evolution and Ecology Program; International Institute for Applied Systems Analysis; Laxenburg Austria
2. Department of Biology; Theoretical Population Ecology and Evolution Group; Lund University; Lund Sweden
3. Department of Mathematics and Mathematical Statistics; Umeå University; Umeå Sweden
4. Section of Theoretical Biology; Institute of Biology and Mathematical Institute; Leiden University; Leiden The Netherlands
5. Naturalis Biodiversity Center; Leiden The Netherlands