Patent leather beetles (Odontotaenius disjunctus), also called bess bugs or jerusalem beetles are large, shiny, black beetles from from the temperate forests of the Eastern United States. They are found in and around rotting wood. These beetles are semi-social and take care of their young. When you collect them keep the adults and larvae from the same area together. They are very simple to care for and adults normally live a year.
A tank of 2 1/2 gallons can hold up to 12 adults. A ten gallon will hold twice that. These beetle will not use the vertical space in the tank so the actual number you can house will depend on how deep your substrate is and the area of the tanks floor. For substrate use soil from where you found them or coco fiber. Keep it moist but not wet. Room temperature is fine for these beetles and they prefer darkness so no lighting is required. For decor use leafs, moss, and of course wood.
Patent leather beetles eat rotting wood from deciduous trees like maple and elm. It is best to collect some of the wood you found them under. Any wood you give them should should be sufficiently old and decaying. I like to give them one or two big pieces and let them build tunnels through it and under it as they would in the wild. These beetles will eat there own waste to build up levels of a certain fungus in their guts. The fungus allows them to digest the wood. They feed a pre-chewed mix of wood and excrement to their grubs. For water simply mist the tank every other day, and anytime you add new wood soak it in water first.
These beetles are very hard and are thus not easily damaged. They make noises when picked up but one must fight the temptation to handle them often. Pickup only those that are on the surface and never go digging through the substrate for them. That will disturb their tunnels. These beetles like to be setup in a spot and not moved often.
If you are lucky your beetles may reproduce, but don’t count on it. They are notoriously difficult to breed in captivity due to how sensitive they are to movement and light.