1. 1Department of Plant Sciences and Biotechnology, Georgikon Faculty, University of Pannonia, Festetics u. 7, H-8360 Keszthely, Hungary
2. 2Kolics Apiaries, Balatonszentgyörgy and Bolhó, Balatonszentgyörgy, Hungary
3. 3Balaton Limnological Institute, Centre for Ecological Research, Tihany, Hungary