1. Department of Cell Biology; Faculty of Biology; Adam Mickiewicz University; Umultowska 89 61-614 Poznań Poland
2. Institute of Nature Conservation; Polish Academy of Sciences; Mickiewicza 33 31-120 Kraków Poland
3. Department of Ecology; Swedish University of Agricultural Sciences; Box 7044 Se 750 07 Uppsala Sweden
4. Department of Behavioural Ecology; Faculty of Biology; Adam Mickiewicz University; Umultowska 89 61-614 Poznań Poland
5. Institute of Zoology; Poznań University of Life Sciences; Wojska Polskiego 71C 60-625 Poznań Poland