There was an error published in Biol. Open2, 901-906.

In Fig. 4D, the y-axis scale was incorrect; the correct Fig. 4 is shown below. There are no changes to the figure legend, which is accurate. This error does not affect the conclusions of the paper.

The authors apologise to the readers for any confusion that this error might have caused.

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.