1. ENFA and UMR 5174 EDB (Laboratoire Évolution & Diversité Biologique), CNRS; Université Toulouse III - Paul Sabatier; Toulouse cedex 9 F-31062 France
2. Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
3. CEFS, INRA; Université de Toulouse; Castanet Tolosan 31320 France
4. Department of Biology; University of Saskatchewan; Saskatoon SK S7N 5E2 Canada
5. Department of Bioscience; Aarhus University; Roskilde 4000 Denmark
6. Department of Mathematics and Statistics; University of Helsinki; P.O. Box 68 Helsinki 00014 Finland
7. Department of Biology; University of York; York YO10 5DD UK
8. Department of Biology; University of Antwerp; Antwerp B-2610 Belgium
9. Station d'Ecologie Théorique et Experimentale; CNRS UMR 5321; Moulis 09200 France
10. Institut De Systématique, Evolution et Biodiversité, UMR 7205; Muséum National d'Histoire Naturelle; Paris cedex 5 FR-75005 France