1. Division of Behavioural Ecology; Institute for Ecology and Evolution; University of Bern; Wohlenstrasse 50A CH-3032 Hinterkappelen Switzerland
2. Institute of Integrative Biology; University of Liverpool; Leahurst Campus Chester High Road Neston CH64 7TE UK
3. Département de Biologie et Institut de Biologie Intégrative et des Systèmes; Université Laval; Quebec Canada G1V OA6