1. Department of Ecology & Evolution; University of Lausanne; Biophore Building Lausanne 1015 Switzerland
2. Institute of Cytology; Russian Academy of Sciences; Tikhoretsky pr. 4 St. Petersburg 194064 Russia
3. The Museum of Nature; V. N. Karazin Kharkiv National University; Trinkler st. 8 Kharkiv 61058 Ukraine
4. Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB); Müggelseedamm 301 Berlin D-12587 Germany