I don't know, I guess that depends on the type of nocturnes in question. They could simply be bug hunting... I very often come across some beetle larvae or grubs when I plant my plants out from the medium - I guess the active microbiology is an attractive environment for them. Then again, I have seen my dogs licking at my potting medium or stealing small pieces of fermented bark from it - so could very well be the minerals or the smell that attracts them. As for my pots - I have but one word - PUPPY!

So great to see you around again, looking forward to a post from you!