Dermestid beetles in terraria
Dermestid beetles can be used as part of a clean-up crew in a (bioactive) terrarium. They eat the carcasses and shed exoskeletons of dead insects like dubia roaches, crickets and isopods. These beetles are true scavangers and will not predate on any living beings. Dermestid beetles are save to eat for any reptile that is present in the enclosure, however, reptiles may dislike the feel of the hairy larvae and rather ignore them.
Watch this beautiful setup of Dr. Plants with 50 dermestid beetles (Dermestes maculatus), harvester ants, dune geckos, darkling beetles, katydids, killifish, fairy shrimps and a camel spider:
I would personally recommend species that don't breed as fast and don't need as much food as D. maculatus for terrariums. My top pick species would be: D. undulatus, D. lardarius and D. murinus.
Here are two examples of my own setups:
Important to keep in mind
Make the terrarium escape proof
Some species gain the ability to fly at lower temperatures than other species. Please check the information on this page to get an idea of the temperatures. If there are any holes present in the terrarium, such as holes intended for electrical cables, please make sure that no material that can be climbed by the beetles reaches this potential exit. Dermestid beetles can't climb on glass, smooth plastic or smooth metal.
Cork bark and / or styrofoam
The beetle larvae bore into certain materials to feel save when they want to pupate. If styrofoam is used for the landscaping or the background is covered in cork bark, the larvae will most certainly bore into these materials. Be aware that these materials will slowly be destroyed over time if they are present in the enclosure and will need to be replaced once in a while.
Dermestid beetles in insect enclosures
Breeders of feeder insects, such as dubia roaches and house crickets, also use dermestid beetles as a cleaner crew. In this specific branche, the species Dermestes ater is most widely used. This species is fond of big dead insects as a food source and the colony grows relatively slow in numbers. Keep all insect enclosures closed. The reason why this species is not as suitable to be kept in a terrarium, unlike the previously mentioned species, is because D. ater is a very flightly species. Especially when disturbed, the adult beetles will try to fly even at room temperatures.
Some food sources can be shared between the feeder insects and dermestid beetles, for example dog kibble and fish flakes. This is a great way to give a supplement to the dermestid beetles when food is scarce while also feeding the other insects and preventing the build up of leftovers.