1. Division of Genetics and Physiology; Department of Biology; University of Turku; Turku 20014 Finland
2. Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; Helsinki PO Box 65 00014 Finland
3. Behavioural Ecology Group; Department of Systematic Zoology and Ecology; Eötvös Loránd University; Pázmány Péter sétány 1/C 1117 Budapest Hungary
4. MTT Agrifood Research Finland; Jokioinen Finland