There was an error published in the original online version of J. Exp. Biol. 214, 1655-1667. This error occurred in both the PDF and full-text versions of the online article. The print version is correct.

The accepted date was incorrectly given as 21 December 2011. The correct accepted date is 21 December 2010.

We apologise sincerely to authors and readers for any inconvenience this error may have caused.