Should I Use Dermestid Beetles in My Dubia Roach Colony?

Visitors asked us to weigh in on whether or not they should use Dermestid beetles and larvae as cleaner crews in their Dubia colonies.

It’s tempting to give a “yes” or “no” answer based on our own experience, but that might discount the experience (or potential experience) of others. In the end, each case is different. Every situation is different, so the decision whether or not to use cleaner crews is an individual one that is at least in part based on a unique set of circumstances and needs.

However, there are also some factors that may apply at least generally, and perhaps across the board. Considerations based on location or environmental conditions, for example, can be circumstantial, but other things (like the fact that we’re dealing with Dubia roaches) may be universal.

Instead of a simple yes or no, we decided to provide anecdotal information about how Dermestidae and other insects work and have worked as cleaner crews in our colonies. We’ll give you the good and the bad – the pluses and minuses – and allow you to decide for yourself whether or not to use them, in light of your unique circumstances.

Our decision to add Dermestes to our Dubia colonies was an easy one. In short, their benefits outweigh their costs. They’re highly effective, they’re the cheapest form of insurance against mold and bacteria-related problems that we know, and they’re easy to maintain. We could almost just drop them in our colonies and forget them. As we discuss in our article about Dubia roach die-off, bacterial overgrowth is dangerous and something you never want to deal with. It can cause grave harm to a colony. Cleaner crews may help avoid it.

So for us, the answer is “yes”.

Important Note:

Since initially writing this article, we discovered that “combination cleaner crews” consisting of both Dermestid beetles and lesser mealworms is more effective than either species alone. We like the two together, and they’re worth considering for your situation. We discuss this in more detail below.

The Problem

Unwanted bacterial growth is among the biggest potential problems with the dark, warm, moist environment Dubia roaches need for growth and reproduction. Combined with poor air circulation and foods bacteria love to eat – like food particles, roach feces, and dead roaches – conditions in a colony can go south in a hurry. Unfortunately, this can have grave consequences. Die-offs are not uncommon among large captive tropical roach colonies, and Dubia roaches appear more susceptible than most.

Cleanliness is a related issue. Roach bins require regular cleaning, and the more humid the environment the more frequent that cleaning needs to be. Neglecting cleaning for too long can lead to an accumulation of frass and food particles. This can contribute to mold, bacterial, and/or fungal growth. This can result can be stress within the colony, which may in-turn lead to growth problems, breeding problems, and even death.

In addition to being a danger to the roaches, moisture build-up and the fungi and/or bacteria that accompany it can cause foul smells. This may or not be an issue depending on how many colonies you have and where they’re kept. For most people, smell is probably an issue. Dubia roaches don’t tend to smell bad, which we consider to be one of their many benefits. This benefit is lost when bacteria is allowed to colonize.

The Solution

Dermestid beetles and larvae, with help from another cleaner species, have reduced and prevented these problems in our colonies.

Dermestid beetles and larvae eat dead roaches. In sufficiently large numbers, they can greatly reduce the amount of decaying organic matter in an enclosure. Because this is fuel bacteria need to grow, bacterial growth can be reduced along with its ability to gain foothold in a colony. In theory, a reduction in bacteria equals a reduction in the risk of harm, and that has been our experience.

Reducing the number of decaying roaches also cuts down on moisture build-up. Moisture can become trapped in dead roaches, especially when they become buried in frass. Colonies with high humidity are the most vulnerable to this danger. Once it starts, this process tends to snowball, and the bin must be cleaned to avoid further (and potentially more serious) issues.

Unfortunately, moisture build-up often occurs beneath the surface, out of sight for the most part. It’s not always apparent, and it may not be noticed until it’s far advanced. As a general rule, moisture reduction lowers the risk of colony harm from bacteria. In our experience, the best ways to reduce moisture are (a) reduce humidity, (b) clean regularly, and (c) add cleaner crews.

The Cost

What does one have to do for all these benefits? Not much, actually. Dermestidae are relatively care-free insects. They don’t require much maintenance, and they’re certainly easier to keep than tropical roaches. It takes more skill to manage a Dubia colony than a population of Dermestidae cleaners. And notably, managing cleaner insects is a lot less work than dealing with a roach colony that has gone bad from neglect. It can be a lot less expensive too. Again – a die-off is a worst-case scenario, but we’ve experienced them. They’re no fun and should be avoided.

Are They Worth It?

So while Dermestid cleaners are relatively easy, they aren’t completely hands-off. They do require at least a little effort to maintain. Most people can probably get away with just adding a batch of beetles and larvae to their colony and checking in from time to time to see how they’re doing, but we recommend taking a little more care with them than that. Learning how to tend to them takes a little time up-front, but once that’s done the maintenance itself is easy. They may, for example, need supplemental food if the colony they’re added to is not large enough to support them yet.

The Upside

For us, the major Dermestidae benefits are less required maintenance, better colony health (less risk), and better smell. It’s easy to let maintenance slip with so many colonies, and the addition of cleaners reduced the number of “health incidences” like die-offs. Less frequent cleaning means less stress for the roaches and less disturbance, and frass serves an important biological function – especially for nymphs. We don’t want to disturb our roaches any more than we have to, and we don’t want to remove any more frass than necessary.

Without cleaner crews, we find that we have to stay on top of enclosure maintenance to avoid health problems within the colony. With them, we can manage more colonies with less effort. And there’s more margin for error. For example, the first sign of trouble in a colony is usually the smell of ammonia. When that happens, we usually find unprocessed dead roaches and moisture build-up in the frass. At this point the bin needs to be cleaned, which is a lot of work. As mentioned, it also disturbs the roaches and deprives them of the frass they need for good health.

But we avoided this almost entirely with the inclusion of Dermestidae cleaners. Further, we had no serious bacterial overgrowth events after adding a combination of Dermestidae and lesser mealworms. We think, as a rule, lesser mealworms compliment Dermestidae by eating plant matter and feces where Dermestid beetles and larvae eat only animal matter. Lesser mealworms will eat dead roaches too, but it seems they don’t prefer to. Outdoors, they’re found in compost piles and animal feces, which seems like a natural fit for a roach bin with substrate consisting of frass. They do seem to be very happy there and we’ve seen them thrive.

All things equal, and in our experience, the combination of the two insects is more effective than either alone. We’ve seen good results in colonies with either species alone, but the best scavenging and cleaning seems to result from using them together.

Read More: About different cleaner species – needs, care, personality (article)

The Downside

Maintaining Dermestidae in roach colonies requires periodic checks to see how they’re doing. This involves looking inside the bin to get a sense of their numbers and activity. This helps alert to any issues early, before they can develop into bigger problems.

It’s important to note that Dermestidae have been reported to be pests capable of eating through floors and walls (external link), but we haven’t seen this. Perhaps we don’t have the right climate here. Be aware that while we haven’t had issues with them, the potential for problems may exist. You should be sure they won’t cause problems for you before you buy them. The same is true for lesser mealworms. They can be a pest in some circumstances. For example, the poultry industry may consider them a pest because they get into chicken manure.

Dermestid beetles and lesser mealworms are both native to the United States and can be found throughout the country.

As for negatives in roach breeding, there aren’t many. They aren’t free so there’s some expense upfront, but that cost is relatively small. They’re another thing to think about when managing a colony. However, as previously mentioned, they’re easy to manage once established, and they reduce rather than increase the number of things roach-keepers need to think about on a day-to-day basis. While it’s possible they could grow out of control, this seems unlikely. It’s certainly never happened to us, and we haven’t heard of it happening to others. Dermestid growth is limited by food, and excess food won’t be available unless there’s a massive roach die-off. In this case, the colony has bigger and more urgent problems than an increasing Dermestidae population.

The same is true for lesser mealworms. Their numbers are limited by food, and their population can be reduced when necessary.

This brings us full-circle back to “the upside” category. We found that as a general rule, if the Dermestidae and lesser mealworms are doing OK within a colony, the roaches are OK too. As such, cleaner crews may serve as a sort of “canary in a coal mine”. They may alert to potential problems with the roaches. So in addition to reducing the likelihood of trouble, they also warn of trouble. This provides us with a certain peace of mind.

Our Conclusion

We’ve seen and experienced some compelling reasons to use Dermestid beetles and larvae as cleaner crews. From a purely functional roach-raising perspective, their benefits substantially outweigh their costs. In combination with lesser mealworm cleaners, they may afford a larger margin of safety than with no cleaner crews, or either of the two species alone. In working with roaches on a large scale, they have definitely made our lives easier. They helped us grow and maintain healthier colonies for less work, and have given us some peace of mind.