We are grateful to Marie-Claire Orgebin-Crist for the helpful discussion and for their critical reading of an earlier version of the draft. We thank Gilles Didier and Manuela Royer-Carenzi for advice on probability calculations, anonymous reviewers for comments that improved the draft, and the Contributions to Zoology editorial staff for its efficient handling of the paper.
Received: 14 October 2014
Revised and accepted: 4 March 2015
Published online: 4 September 2015
Editor: J.W. Arntzen