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 at least a little different, and every situation is unique.
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 universal. The fact that we are dealing with Dubia roach colonies is one example.
Instead of a simple yes or no answer, we provide anecdotal and other information about how insects work and have worked as cleaner crews in our colonies. We’ll report to you the good, the bad, and the ugly and allow you to decide for yourself whether to use Dermestid beetles or other cleaner crews in your Dubia colony, 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, they are the cheapest form of insurance against mold and bacteria-related problems we know, and they are 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 and something you want to avoid. It can cause grave harm to a colony, and cleaner crews may help you avoid it.
So for us, the answer is “yes”.
Since writing this article, we discovered that combination cleaner crews consisting of Dermestid beetles and lesser mealworms are more effective than either species alone. We like the two together and think they are worth considering for your situation. We discuss this in more detail below.
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 common 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 cleanings must be. Neglecting cleaning for too long can lead to an accumulation of frass and food particles. This material build-up contributes to mold, bacterial, and fungal growth, which can cause colony stress. Colony stress is a generalized condition that can lead to problems like slow growth, reduced breeding, and even death. These are all things you want to avoid.
In addition to being a danger to the roaches, moisture build-up and the fungi and bacteria that tend to follow 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. However, this benefit is lost when bacteria colonize a Dubia colony.
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 the fuel bacteria need to grow, bacterial growth can be reduced along with its ability to gain a foothold in a colony. In theory, a reduction in bacteria equals a reduction in the risk of harm, and this concept has proven true in our experience.
Reducing the number of decaying roaches also cuts down on moisture build-up. Moisture can become trapped in dead roaches — especially ones buried deep in frass. Colonies with high relative 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 bacteria will harm a colony. In our experience, the best ways to reduce moisture are (a) reduce humidity, (b) clean regularly, and (c) add cleaner crews.
What does one have to do for all these benefits? Not much, actually. Dermestidae are relatively carefree insects. They don’t require much maintenance and 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 to keep, they’re not completely hands-off. They 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 occasionally to see how they’re doing. However, 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 you’ve done that, 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 main 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. Adding cleaner crews to them 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 be more strict with our enclosure maintenance to avoid health problems in our colonies. Cleaner crews allow us to manage more colonies with less effort. And they give us more margin for error. For example, one sign of colony trouble is 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 troublesome bacteria overgrowth after adding a combination of Dermestidae and lesser mealworms.
We think, as a rule, lesser mealworms complement Dermestidae by eating plant matter and feces, whereas Dermestid beetles and larvae eat only animal matter. Lesser mealworms will eat dead roaches too, but they don’t prefer it. Outdoors, Lesser mealworms live in compost piles and animal feces, which seems like a natural fit for a roach bin with frass as a substrate. They do seem to be thriving and very happy there.
All things equal, 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 results from using them together.
The downside of cleaner crews
Maintaining a colony of Dermestid beetles and larvae in roach enclosures requires periodic checks to see how they’re doing. These checks involve looking inside the bin to determine their numbers and activity. Getting a sense of how they’re doing helps alert us to any issues early before they can develop into bigger problems. Occasionally, we decide to reduce their numbers in one colony or several, which is a relatively straightforward process.
That’s it for the downside. Not bad.
It is important to note that Dermestidae has 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 pests because they get into discarded chicken manure.
Dermestid beetles and lesser mealworms are native to the United States and are 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 consider when managing a colony, as previously mentioned, but they are relatively carefree and hearty creatures. Once established, they tend to reduce the number of things we need to think about daily 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 and Lesser mealworm growth is limited by food. Excess food will not be available unless there is a massive roach die-off or care and cleaning are neglected. If either of these is true, a colony has bigger and more urgent problems than a growing cleaner crew population.
And again, the numbers of either species (or both) can be reduced when desired.
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.
We have seen and experienced compelling reasons to use Dermestid beetles and larvae 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, Dermestid beetles and larvae 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 they have given us peace of mind.
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