1. Department of Psychology and Neuroscience; Life Sciences Centre; Dalhousie University; Halifax Nova Scotia Canada B3H 4R2
2. Faculty of Engineering and Science; Jacobs University Bremen; Campus Ring 1 28759 Bremen Germany
3. Department of Biology; Oulu University; P.O.Box 3000 SF 90014 Oulu Finland
4. Department Cytology and Evolutionary Biology; Zoological Institute and Museum; Ernst-Moritz-Arndt-University Greifswald; Soldmannstrasse 23 17487 Greifswald Germany