We apologize but I made a mistake in writing our funding statement. Namely, instead of "KP: Polish National Center for Science, funds granted by decision number DEC-2012/05/D/ST7/02072. No funds were given to KP for publication fees" one must read "KP: Polish National Center for Science, funds granted by decision number DEC-2012/05/D/ST7/02072. " Indeed, KP reveived funding (as certified by the paid fees) for publication by the "Polish National Center for Science".
The error has been communicated by me to PLoS CB and formal correction is being prepared, which will be soon available on PLoS CB.
Alberto d'Onofrio (corresponding author)