I just saw this on pipe maker Chris Askwith's Instagram: a picture of a beetle eating a horn shank extension!
http://instagr.am/p/B3eCGGvHbb0/Make sure yours are safe! Your horn extensions, that is, not your horn eating bugs. ?
All my horn adorned pipes are long gone though I may have to check my ivory, tooth, and bone accents. I've never seen any carpet beetles around here so I'm probably safe.
I guess most materials having protean content are edible and digestible by some other living creature. People certainly take part in this quest for calories and nutrients. This makes my faux horn ferrule pipe look especially good. Those Vuillard people knew what they were doing.