Acknowledgments
We thank two anonymous referees, Tomer Czaczkes, Sebastian
Pohl and Magdalena M. Mair for valuable comments. Thanks to
Hannah Fried-Petersen for checking the orthography. Additional
thanks go to Daniel Schließmann and Max Kölbl for assistance in
the field. We are grateful for financial support from the DFG
(Deutsche Forschungsgemeinschaft, Project WI 2646/7-1).