There were errors published in Biology Open (2018) 7, bio031849 (doi:10.1242/bio.031849)

D. Strubbe's second affiliation and funders were omitted from the original manuscript. This has now been amended in the online version.

The author apologises for any inconvenience.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.