1. Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, 3032 Hinterkappelen, Switzerland
2. Neuchâtel Platform of Analytical Chemistry, Institute of Chemistry, University of Neuchâtel, Avenue de Bellevaux 51, 2009 Neuchâtel, Switzerland
3. Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland