1 Division of Evolutionary Biology, Department of Biology, LMU Munich, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany. holtmann@biologie.uni-muenchen.de.
2 Behavioural Ecology Group, Department of Biology, LMU Munich, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany. holtmann@biologie.uni-muenchen.de.
3 Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 14-18, 75236, Uppsala, Sweden.
4 Division of Evolutionary Biology, Department of Biology, LMU Munich, Großhaderner Straße 2, 82152, Planegg-Martinsried, Germany.