Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE 405 30 Göteborg, Sweden and Department of Biology, Faculty of Sciences, University of Dicle, 21280 Diyarbakir, Turkey Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE 405 30 Göteborg, Sweden and Department of Biology, Faculty of Sciences, University of Dicle, 21280 Diyarbakir, Turkey.