Apologies in advance for an extremely wordy post, but since so little is know about the biology of these I feel it is all relevant, especially if I am not successful so future keepers can know what has been tried. Please add more if you have experience with these or know someone who does.
Well it looks like they mated, I just got an enclosure set up for them. 1.5-2 inches of organic potting soil (a decent amount of mycelium in it) with a couple of logs. The first logs I'm trying are hardwood, likely oak, approximately 2.5 inches in diameter, and that are quite hard. These have been noted to lay eggs in bark crevices, and I suspect that logs are required for oviposition. I daresay the logs really not rotten at all, more in line with a dead branch attached to a live tree. This level of wood I would generally reserve strictly for longhorn beetles or infecting with something like oyster mushrooms. Plenty of lichen in the setup for the adults, although I haven't observed them eat yet. In addition I scraped some slivers off of a woody bracket fungus (both the mycelium side and the body) into a corner of the setup, I am curious to see if they show any interest in it.
I am keeping the setup quite humid, about what you would do for a rhinoceros or stag beetle from the southeastern US. The conditions I found them in were quite in line with a muggy Georgia deciduous forest, even swampy in several parts, and I suspect that people trying to breed these in desert conditions may contribute to the lack of success in captivity for this species. These are not desert beetles, in fact the substrate was leaf-littered dirt where they were collected, no sand in sight. That being said, these seem to tolerate a wide range of conditions and slightly more dry is likely better than slightly too damp.
Things of note/observations: almost every beetle I found is imperfect, three of them are missing a front leg and one of them is missing a tarsal claw. I'm unsure if this relates to their age, attempts at predation in their specific area, or if these beetles have a tendency to lose limbs, which seems odd for such an "indestructible" beetle. Adults were found almost exclusively in pairs, with what I can only assume is the male chasing the female up a tree. These were found exclusively on hardwoods with loose bark, lots of lichen, and dead parts (usually in the form of a dead branch). Considering I found more in one night than most people will in years, I consider this to be a strong correlation. While I haven't been able to find out what a larva of this species looks like, depictions of other family members resemble that of some bark beetle larvae and others that spend the larval period under the bark of decaying hardwoods. This leads me to suspect that these beetles require firm rotting logs with an intact bark layer, and that the larvae live under this layer. That's just my hypothesis though.
With all that, hopefully I am successful here. Having a group of five (and I do intend to collect more) is a huge opportunity since I haven't heard of people having more than one or two at a time.
