Visitors periodically ask us to weigh in on whether or not they should use Dermestid beetles and larvae as cleaner crews in their Dubia roach colonies. It is tempting to give a “yes” or “no” answer based on our experience, but that might discount the experience (or potential experience) of others. What happens in one colony may not happen in another. In the end, each case is different. The decision of whether or not to use cleaner crews is an individual one at least partly based on a unique set of circumstances and needs.
That said, there are some general concepts that may apply across the board, or nearly so. While location and environment, for example, are circumstantial, other things are more universal. The fact that we are dealing with Dubia roach colonies is one example.
Instead of a simple yes or no, we decided to provide anecdotal and other information about how Dermestidae and similar insects work and have worked as cleaner crews in our colonies. We’ll give you the good, the bad, and the ugly and allow you to decide for yourself whether or not to use them, given your unique circumstances.
Our decision to add cleaner crews
Our decision to add Dermestes to our Dubia colonies was an easy one. In short, their benefits outweigh their costs. They are highly effective, the cheapest form of insurance against mold and bacteria-related problems we know, and easy to maintain. We could almost just drop them in our colonies and forget about them. As we discuss in our post about Dubia roach die-off, bacterial overgrowth is dangerous. It is something you never want to deal with because it can cause grave harm to a colony. Cleaner crews may help avoid it.
So for us, the answer is “yes”.
Important note:
Since 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 we think they are worth considering for your situation. We discuss this in more detail below.
The problems
Unwanted bacterial growth is among the biggest potential problems with the dark, warm, moist environment Dubia roaches need for growth and reproduction. When combined with poor air circulation and the foods bacteria love to eat – like food particles, roach feces, and dead roaches – conditions inside 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 is, the more frequent cleanings must 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 in turn can result in colony stress. Colony stress may lead to growth problems, breeding problems, and even death. More bad stuff.
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 for you depending on how many colonies you have and where you keep them. Smell is probably going to be an issue for most people. Dubia roaches don’t tend to smell bad, and we consider this one of their many benefits. The benefit is lost when bacteria 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 this has born out in our experience.
Reducing the number of decaying roaches also cuts down on moisture build-up. Moisture can become trapped in dead roaches, especially the ones buried deep 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 is not always apparent, and you may not notice it until it is far advanced. As a general rule, reducing moisture lowers the risk a colony will be harmed by 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 are easier to keep than tropical roaches. Managing a Dubia colony requires more skill 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 you should work hard to avoid them.
Are cleaner crews worth it?
While Dermestid cleaners are relatively easy, they are not completely hands-off. They do require at least some maintenance effort. 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 roach colony is too small to support them.
The upside of cleaner crews
For us, the major Dermestid benefits are less required maintenance, better colony health (less risk), and better smell. It’s easy for us to let maintenance slip with so many colonies, and the addition of cleaner crews reduced the number of health-related incidents like moisture accumulation and 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 is necessary.
Without cleaner crews, we find that we have to stay on top of enclosure maintenance to avoid health problems within the colony. With cleaner crews, we can manage more colonies with less effort. And there is more margin for error. For example, the first sign of trouble in a colony is usually the smell of ammonia. When that occurs, 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 it. Outdoors, they are 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 thriving and very happy there.
All things equal, and in our experience, the combination of the two insects is more effective than either alone. We have had good results in colonies with either species alone, but the best scavenging and cleaning seems to result from using them together.
The downside of cleaner crews
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. We occasionally decide to reduce their numbers in one colony or several. This is a fairly easy process.
That’s it for the downside. Not bad.
It is important to note that Dermestidae have been reported to be pests capable of eating through floors and walls (external link). We have not seen this. Perhaps we don’t have the right climate here. Whatever the case, be aware that while we have not had any issues, the potential for problems may exist. You should be sure they will not cause problems for you before you buy them. The same is true for lesser mealworms. They may be a pest in some circumstances. For example, poultry producers consider them a pest because they get into discarded chicken manure.
Dermestid beetles and lesser mealworms are both native to the United States and can be found throughout the country.
As for any negative impacts of cleaner crews on roach breeding, we have not experienced any. Cleaner crews are another thing to think about when managing a colony, as previously mentioned, but they are fairly care-free creatures. Once established, they tend to reduce the number of things we need to think about day-to-day rather than increase them.
While a possibility exists that they could grow out of control, this seems unlikely. It has never happened to us, and we have not heard of it happening to others. Dermestid growth is limited by food. Excess food will not be available unless there were a massive roach die-off. In this case, the colony has far bigger and more urgent problems than an increasing Dermestidae population.
The same is true for lesser mealworms. Their numbers are limited by food, and reducing their population when desired is easy.
This brings us full-circle back to “the upside”. We found that as a general rule, if the Dermestids and lesser mealworms are doing OK in a colony, the roaches are OK too. As such, cleaner crews may serve as a trouble notification system. A sort of “canary in a coal mine”, if you will. They can alert to potential problems with the roaches. So in addition to reducing the likelihood of trouble, they also warn of it. This gives us a certain peace of mind.
Read more: The complete guide to caring for Dubia roach cleaner crews »
Our conclusion…
We have seen and experienced compelling reasons to use Dermestid beetles and larvae along with lesser mealworms and beetles 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 for a colony than one without them. We work with roaches on a large scale, and cleaner crews have made our lives easier. They have helped us grow and maintain healthier colonies with less work, and have given us peace of mind.
alexander says
I had 1 question im currently using the beetles as cleaner crews I always have trouble when cleaning I end up throwing a lot away when I clean my tub every 4 months I started to clean every six months to try and keep them working longer but I was just wondering if you had any tips on separating larva and beetles from frass , thank you all your information is useful and greatly appreciated
DRD says
A bucket with very small holes may work, but I don’t think that’s necessary. Some frass is always a good idea. When we clean Dubia Roach bins we remove all the frass, clean the bins, then add some of the frass back, sifted and cleaned as much as possible. This will contain cleaner crew beetles and larvae and the cleaner crew population always bounces back quickly. Not having enough cleaner crews has never been a problem. You can easily wait several months between cleanings, and if there is a spill or some mold develops you can spot clean or remove frass from an area not affected, clean the bin, then add back the clean frass you removed.
Nancy Johnson says
I think I added too many cleaner beetles (in this case tenebrio obscura) to my young dubia colony. I bought less than 150 roaches, all sizes but no adults. Then I read about adding cleaner beetles and added 100 of those.
The problem, as I see it, is the beetle larva is now eating all the dubia food. Maybe I should have waited until the roach colony was mature and reproducing before adding beetles? I recently started feeding my roaches Repashy bug burgers and was so impressed because it was disappearing overnite! Haha, I realized it is the beetle larva eating it! I guess there isn’t enough dead or discarded roach skins to feed them. The floor of my bin, and the food dishes are a writhing mass of larva and they are climbing the egg crates! How can that not be stressing out the roaches?
The dubia should have babies any time now. How do I really reduce the beetle larva (very tiny to 1/2″) without reducing the frass that the roach nymphs will need? (I was ready to get rid of the beetles/larva until I read the above information. Now I don’t know what to do…)
Any suggestion?
DRD says
We’ve come up with a simple and very effective way to way to reduce the number of cleaner insects in a Dubia colony.
Find a small container around 1 to 3 inches tall. The sides should be smooth enough that the cleaner insects can’t climb them. We use plastic, but glass would probably work well. It needs to be high enough that the insects can’t climb out and wide enough that it can be wedged between harborage so that it’s touching multiple areas where the cleaners crawl. You could also make a “bridge” over the top of the container.
Add a small amount of food and set the container in the enclosure. Beetles and larvae will fall in. Check it often, because roaches may also become trapped. Ideally, you can find a shallow container that will trap all of the cleaners but some of the roaches can climb out.
That’s it. Empty and repeat. This method is surprisingly effective at reducing the number of cleaner crews in a colony, and it works fast!
Kimberly says
I read about someone freezing and keeping frazz for later use. If you get insects cold it will slow them down and make it easier to sort them. Would probably kill the roaches but could apply it to the beetles and larva sorting.
Amanda says
What is “frass”??
DRD says
“Frass” is the name of the material that accumulates over time in Dubia roach and other insect colonies. It’s made up of discarded shell, feces, uneaten food, and other debris.
bill says
I have super worm beetles can I use them for cleaners in my Dubias I have a colony tank and and my feeder tank ?
DRD says
Interesting question. I don’t know the answer, but I lean toward “no” for a few reasons.
I would be concerned that superworms/beetles could stress the roaches. They’re large, and if memory serves, the worms bite in their search for food. I don’t recall if the beetles bite or not (it’s been a long time since I’ve fed superworms). If they do, this alone would be enough for me to avoid them. Roaches are extremely vulnerable when they molt, and even their fellow roaches occasionally take bites out of them before their new skin hardens. There is a chance superworms and beetles, because they are so large, may consider molting roaches food.
Superworms also burrow like lesser mealworms, but because of their size they could conceivably tear up paper-based harborage pretty fast. This is all just a theory though, so to find out I think someone would have to try it and see what happens. It’s possible that it could work, but these would be my concerns.
bill says
thank you . I hadn’t thought about them biting my roaches I wouldn’t want them bitten or my babys bitten or ate ‘ or stressed out’
Michael Jarvis says
I have had the occasional superworm get into a dubia colony, not a good experience for mine. Once they matured into beetles, the dubia avoided being anywhere within several inches of them, to the point of one side of the box being so crowded that the roaches covered their entire surface area of egg carton, and the side with just two beetles being nearly absent of dubia. My guess is the noxious odor of the beetles, as the larva were ignored. I would expect a similar yet weaker reaction to the regular mealworm beetles, since they smell almost as bad, although not as potent.
DRD says
Interesting observation about superworms. We have not seen the same thing with lesser mealworms, but it’s certainly possible that they could pose some degree of annoyance to Dubia roaches. If there is a trade-off between cleaning ability and negative impact on a colony, the lesser mealworm population can be held low with regular cleaning. They can even be eliminated entirely with a little diligence. You can do this by removing as many of the beetles and larvae as possible with a thorough bin cleaning. Then check daily for beetles until none remain. Only beetles lay eggs so you want to remove beetles as they emerge, before they can become gravid. I’m guessing you may have already figured this out in dealing with your superworm problem.
Anonymous says
I’m soon getting a dubia roach colony, and from what I’ve read, the “substrate” you keep them in is frass (as they produce it over time). But your lesser meal worm and dermestid beetles seem to be shipped in some earth or dirt. Do I just throw them in the dubia bin with earth and all when I get them, or do I have to pick them out and put them in?
DRD says
We often ship dermestid and other cleaner crews in their own frass. That is what resembles dirt. The insects are small so their frass is small too. You can separate the insects from their frass if you like, but it may contain some eggs, so the best (and easiest) thing to do is dump the entire contents of the cleaner crew container into your Dubia colony.
Gary says
Great info here!!! I have just started a Dubia “colony” and was wondering if you suggest introducing cleaner crews immediately or waiting. If I should wait, then How long?
Thanks,
DRD says
Rather than making up a rule, I’d base the decision of when to add cleaner crews on the needs and conditions of the colony and your unique situation. Generally, it’s going to depend on colony size and conditions in and around the bin.
Excess waste build-up in a captive roach colony is the primary issue. Signs of it include moist frass, clumping, foul smells including ammonia, and mold or mildew. There may also be fly larvae and flies in and around the bin. Cleaner crews can help mitigate these problems. If you have any of them now, it is time to consider adding cleaner crews.
However, I’m not aware of any benefit to cleaners beyond their potential to remove excess waste. Remember that frass is beneficial for roaches. If it wasn’t, you could just clean out the bin once or twice a week and forget the cleaner crews. So ideally you want to leave some frass in the colony. But frass also makes conditions that could harm the colony more likely. The trick is finding a balance between sterility and excess that works for both you and your colony.
The bottom line is that if you have a small colony that produces little frass and there’s no problem with waste build-up, you can probably hold off on cleaner crews if you want. But you could also add them if you want. If you add them early you have to consider sustaining them, which is covered in the article. On the other hand, cleaner crews may help if your colony has any of the issues above. Of course, there’s a lot of ground in-between, so it’s a judgment call that takes your unique situation into account.
Taylor says
I raise mealworms; would a clean up crew be effective in reducing frass and the dead?
DRD says
It seems unlikely on the surface. Cleaner crews include lesser mealworms and Dermestid beetles/larvae. The lesser mealworms would probably compete with the regular mealworms for resources, and there may not be enough dead mealworms to sustain a Dermestid population.
However, you could give it a try if you wanted to experiment.
Alex says
How much frass does a colony need and why do they need it? I am starting a discoid colony as dubia are illegal in my state. I have been picking the nymphs out and putting them in a separate bin. Should I not do this?
DRD says
It’s probably best to keep a little frass in with the roaches, especially the nymphs. For Dubia nymphs, frass provides nitrogen and bacteria for digestive system colonization, which is important. This is probably the case for other roach species as well, though how important may vary species to species. The bottom line is that frass is probably not critical for captive roach survival, but it may tend to improve their health and colony viability.
Josh S says
I am assuming that the cleaners cannot clime the walls of a typical tote? If a bearded dragon were to accidentally eat one would it harm them? Thanks
DRD says
Correct – neither cleaner species can climb smooth plastic typical with many totes. If it’s rough, they may be able to. And no, neither insect poses any general harm if ingested by a bearded dragon or other animal. Lesser mealworms are related to regular mealworms, and animals tend to avoid the beetles because they secrete a substance they don’t like.
Emma V. says
Love the article! Very informative and comprehensive! Do Dermestid beetles and lesser mealworms require any kind of substrate at the bottom of the roach bin?
DRD says
No additional substrate needed.