I thought I'd post an update after a month of keeping these beetles.
I collected about 20 of them after dark, crawling over the surface of dry rotting timbers of a collapsed barn (certainly more than 100 years old).
I set them up in a 17 quart plastic tub with low ventilation, and tried to include just about anything they might possibly need – an ample substrate of damp rotting wood and leaves, rotting hardwood pieces, slabs of lichen and fungus covered bark. There's a slight vertical humidity gradient, as a layer of sphagnum below the substrate keeps it damp below, but as the wood and bark pieces stack upward I keep them dry at the top.
I haven't seen them eat any food I supplied. I've tried dog food, cat food, carrot, apple, various fungus/lichens, lettuce, fish pellets, squash. I've put in small soft bodied invertebrates in case they are predatory as I've read in a few places (springtails, dwarf tomentosa isopods, baby scaber isopods, chopped earthworms, mealworms (living and dead), fungus gnat larvae, a couple small long-horned beetle larvae). I haven't seen them eat, and I almost never see them moving about in any numbers (just 1 or 2 after dark most nights).
It appears they're putting most of their energy into chewing into the rotten wood pieces in their enclosure. As far as I can tell, they're all boring through the chunks and spend most of their time there.
I don't know what this means. Maybe they're eating the wood? Of maybe they're desperately searching for the food they need which is typically found within wood?
If anyone has any thoughts or suggestions, feel free to reply. Thanks!
