1. Department of Biology, McGill University, 1205 aveune Docteur Penfield, Montreal, Québec, Canada H3A 1B1
2. Institut des Sciences de l'Evolution, Université Montpellier II, CNRS, IRD, UMR 5554, CC65, Place Eugène Bataillon, 34095 Montpellier, France
3. Laboratoire Ecologie-Evolution, UMR 7625 UPMC-ENS-CNRS, Ecole Normale Superieure, 46 rue d'Ulm, 75005 Paris, France
4. Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
5. Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA