1. Ecology and Evolutionary Biology; University of Arizona; Tucson Arizona 85721 USA
2. Département de Biologie; Université de Sherbrooke; Sherbrooke Quebec J1K 2R1 Canada
3. CNRS; CEFE UMR 5175; Université de Montpellier-Université Paul Valéry-EPHE; Montpellier 34293 France
4. Santa Fe Institute; Santa Fe New Mexico 87501 USA
5. Biology Department; McGill University; Montréal Quebec H3A1B1 Canada
6. School of Biology and Ecology; University of Maine; Orono Maine 04469 USA