My Osmoderma were doing fairly poorly (I lost one to unknown causes; it may have starved unfortunately) on the wood I had been giving them, so I decided to go out a'searchin' for wood. I went to an area about 2 miles from my house that has a good stag beetle population, however the areas I could reach flood over every spring so the wood never has any larvae in it. I collected a few hunks of wood that looked a tad bit decayed and offered it to my Osmos; At first I found them in the original wood I gave them, but today a checked and all 3 of them have found their way into the new wood and are just DEVOURING it.
Just thought I'd share my success story; There is PLENTY of wood in the flooded area so I should be able to keep them fed for many generations.