Embaphion spp. (Pie-dish Darkling Beetles)

Housing:

Adults and larvae can be housed together, the enclosure can be anything from a gallon Tupperware or a 10 gallon tank, depending on just how big you want your colony to get. Both species require a lot of ventilation in the breeding enclosures, as adults are very sensitive to high humidity and stuffy air. They should have a substrate of sand, coconut fiber, or a mix of the two, preferably at least an inch or two deep.

Most of the enclosure should be kept bone dry, with a corner or two kept moist at all times for oviposition, and for the larvae to retreat to, (they can't handle completely dry conditions). Alternatively, if the enclosure and substrate is deep enough, (4+ inches of substrate), you can use a vertical moisture gradient, (keep the lower layers of the substrate moist, with the upper layers dry), however this will only work in a pretty deep enclosure with a ton of ventilation, as adults are very sensitive to excess air humidity. It can allow for larvae to pupate successfully in the same setup as the adults though, so if you have the room to dedicate a big tank or bin for them, it will make things easier in the long run.

Hides in the form of toilet paper rolls, egg cartons, cork bark, drift wood, fake plants, cholla wood, etc., should be provided for the adults. Keep in mind that the larvae tend to drag hides underground, so be prepared to lift them up from the substrate regularly.


Diet: 

Adults and larvae will feed on dog/cat/chick food, fruits and veggies, with a definite preference for protein rich foods. Larvae will also feed on rotten wood and dead hardwood leaves, not that they are a necessary component to their diet.


Temperature:

Room temps from 68-75F° work nicely for all life cycles. Excessively warm and humid conditions may cause damage to pupae.


Breeding/Life cycle:

Adults can live 1-3 years under perfect conditions, however they are can be sensitive to humidity fluctuations and overcrowding, so in larger colonies, many don't make it to the two year mark. Each female lays several dozen eggs soon after maturing, usually taking a month or two break between clutches, sometimes an entire season (some localities could need a winter diapause for consecutive batches of eggs each year). The eggs take about 2-3 weeks to hatch, and the resulting larvae are tiny and agile, thus they often go unnoticed until they molt a few more times.

The larvae take 3-4 months to reach maturity, after which they seek moist substrate to burrow into and make their pupal cells. Like most desert Tenebrionid larvae, pupal cells are constructed by pushing substrate away from themselves until they clear a little room in the dirt. They do not reinforce their pupal cell walls with frass or spit like Scarabaeoid beetles do, so they must build their cells in moist, compressed substrate, otherwise the walls can collapse and kill the pupae within. When the larvae reach maturity, (they'll be a little longer than the adults they came from), it is suggested that you isolate them and place them in poorly ventilated, small deli cups (2 oz ones work great) filled with moist, compressed substrate. With any luck, they will burrow down and create a pupal cell near the bottom.

Sometimes in a large colony, larvae will attempt to pupate in the moist areas of the enclosure, and through the burrowing actions of their brethren, get pushed up to the surface. These "pre-pupal" larvae are easy to tell apart from other larvae, as they are immobile, and normally curl up into a J shape. They should be removed ASAP and moved to deli cups with a thin, smooth layer of moist coconut fiber. Sometimes they will pupate successfully in these conditions, other times they die, but it's better than leaving them in the main colony, where they will certainly be eaten. If they do pupate successfully, try to keep them face down, as this is the best position for them to eclose in. Keep the pre-pupal larvae and pupae moist, but never spray them directly, as contact with water droplets seems to kill them.

After a week or two of staying in the pre-pupal position, the larvae will molt into pupae. The pupae take only 2-3 weeks to finish development, after which they molt into soft, teneral adults. Once you notice your pupae have turned into adults, or after they claw their way to the surface from their pupal cells, (whichever comes first), you have to move them ASAP to well ventilated deli cups with bone dry substrate, and offer just one or two drops of water in one area for moisture, as well as give them a small amount of food. If the adults stay in their humid pupal setups too long, they will die. You have to move them very gently though, because they are still soft, and their elytra can easily be dented and deformed permanently at this stage.

Keep the new adults in isolation for 2-3 weeks, once they have finished hardening up, they can safely be handled, and put back in the main colony.