So you’re thinking about starting a Dubia roach colony and you want to know how many roaches you need. This is a common question, and there is an objective answer.
However, in addition to the natural growth rate of Dubia roaches, your answer to this question also depends on you and your situation. For your answer to be meaningful, you need to determine your goals for the colony.
The following information will help you do both.
Colony growth is a function of time
Identifying your goals involves answering a few basic questions about your intended colony size and function. For example, do you want the colony to supply a steady stream of feeders? If so, how many and how often? Do you just want a big colony without concern for feeders? If so, how big do you want it to be? And importantly, when do you want it to be that big? Is next year OK or do you want it sooner?
The reason the answer to the “how many roaches do I need…” question depends on you and what you want for the colony is because there is no set number of Dubia roaches required to start a colony. In theory, you only need one pregnant female. Or you can start with a single male and and a single female…or several of each…or a dozen, hundred, etc.
Obviously then, how fast this potential colony grows and how soon it reaches the size you want is the real question. If you want a colony of 10 roaches, starting with just a few is probably fine. However, you will need to start with many more if you want a colony of 10,000 in a reasonable amount of time. But how many more, and in what time? These are the questions at hand.
The first step toward finding an answer is determining your needs and expectations. From there it’s easy to figure out the number of Dubia roaches you need to start a colony that will do what you want, when you want. So decide on a goal. From there we can use Dubia roach reproductive physiology to calculate a starting point. It’s sort of a “reverse engineering” approach to building a colony, if you will. The estimate is rough, but the numbers work. The rest is in the implementation.
Let’s start with the basics:
Dubia roach reproductive timeline
All things equal, newborn Dubia roaches reach adulthood in about 5 months. Newly emerged males begin mating almost immediately while newly-emerged females start about a week later. Females can become pregnant as soon as they begin mating, and their gestational cycle is 65 days. This means the earliest a female can give birth to a batch of nymphs is 72 days after the day she reaches adulthood. This is roughly 220 days after she is born.
We estimate that females give birth to about 25 nymphs in the conditions common to home Dubia roach colonies. The actual number may be more or less, but 25 is a reasonable average. They repeat this every 65 days.
Colony population estimate
So let’s say, for example, that you start a new colony on day 0 with 5 newly-emerged females and one male. You can expect 125 newborn nymphs in 2.5 months, then again every 65 days after that. Assuming a 75% survival rate and a 50/50 male:female ratio, the first nymphs born will begin giving birth at about 7.5 months. At this time you will have about 50 adult females and 1,250 nymphs.
At 7.5 months, the population begins some pretty serious exponential growth as the first batches of nymphs begin having babies of their own. This is a good cut-off point. At this time you will have a colony with many thousands of roaches whether you started with 10 adult females, 50, or even 100. If you can wait a year, this discussion is largely irrelevant. At that time almost any starting number will yield many thousands of roaches of all ages.
But this takes a year. You may decide that’s too long to wait to reach your population goal for the colony. What can you do if you don’t want to wait? How many females should you start with to have 1,000 nymphs in four months? How about three months? What if you don’t want to wait a full 7.5 months for the roaches to complete one reproductive life cycle and for the colony to become self-sustaining?
Estimates refined: the population graph
You’re in luck! We put together the following graph using the formulas and averages mentioned above. The data is based on the most accurate estimations of the Dubia roach life and reproductive cycles we could find. You can use it to estimate population start and endpoints. This means you can decide what you want your Dubia roach colony to be, use the information above to determine how many roaches it takes to be it, then plot how many you need to start with to get there.
The data essentially allows you to plot nymph population as a function of starting female population and time. You can figure out roughly how many nymphs you’ll have in a new colony at any given point in time between 0 and 200 days, given an initial starting female population of between one and maybe 60 or 70. Again – rough estimates. You can extrapolate population based on higher starting numbers or more time, but as you can see, the population goes exponential. We actually removed some data (starting populations of 75 and 100) because the scale necessary to display such high numbers made the lower results impossible to read. It’s fair to extrapolate though, if that fits your situation.
NOTE: “Total population” is nymphs plus adult females, so just subtract the number of females from the total to get rough nymph numbers. If you know how many nymphs you want the colony to have at any given time, you can estimate the number of females you’ll need to start with to get there.
Summing it up…
So that’s basically it. Colony size as a function of starting female population and time. Or, work backwards to hit a population target. Simple. This should answer the question of how many roaches you need to start a Dubia colony. Keep in mind though that while these projections are based on real averages and actual Dubia roach physiology, your mileage may vary. Factors influencing Dubia reproduction and colony population growth are many. They include temperature, food availability, crowding, stress, etc. We’ve written about these things in our Dubia Roach Breeding Guide, which we recommend reading if you’re interested. Learning about Dubia roach breeding is the logical next step in planning and implementing your new colony.
Related reading…
We’ve also written several other in-depth articles on related topics that you may find interesting, including one on maximizing the natural B. dubia growth rate and another on diagnosing and curing Dubia roach breeding troubles.
Have a question?
If you have a question, please feel free to ask! You can use the comment form below.
Hal says
How many nymphs can you take a week if you start with a 250 roach colony? I have a 3 month old beardie.
DRD says
The short answer is it depends on productivity and what size nymphs you feed your beardie.
All our colony growth projections are theoretical and made with assumptions that don’t apply to each situation. Our best advice is to focus on providing proper nutrition and environment for your roaches. Observe the results, then decide how many nymphs to feed off each week. With a small colony, you may only want to feed off a few or hold off feeding any nymphs until the colony size increases.
Caden says
Hi. I have 25 large roaches. If I use 2 per week, do you think they will grow to be to much for me? I have them in a fairly small box.
DRD says
Assuming these are adults and half are females, they will last 12 weeks. It is likely that some of the females will have offspring in this time, but if you are feeding your animal large roaches, these offspring will be too small to feed off and will need more time to grow.
Your small colony seems unlikely to grow out of control, given what you describe. Chances are that if you want to grow the colony, you will need to manage them for that purpose by feeding your animal fewer roaches than you have until the colony is bigger. At some point you will reach an equilibrium where you gain as many roaches as you feed off, but it sounds like you aren’t there yet.
Wats says
I rescued an adult bearded dragon and want to start a colony to feed him 20 roaches a week because he’s under weight. Is it possible to maintain roughly that number?
DRD says
Yes of course. What size colony you need will depend on what size roaches you will feed him and how close to optimum you maintain the colony. The better the maintenance and the smaller the roaches, the fewer adults required.
Ashley says
I was wondering if I can have 1 male and 1 female dubia to start a colony
DRD says
Yes, you could start a colony with just one female. It’s going to take a while for that female’s offspring to mature and have nymphs of their own, but all things equal, it’s certainly possible.
Betty says
Thank you so much for all this information it’s the best I’ve seen . I will be looking what other things you have . I have started a colony because I live in remote Montana and when COVID hit the pet store would only sale me 10 crickets at a time ( and pet store is 1 12/ hours away . My question is at what stage can I pull feeders out for my bearded dragon without hurting my colony ? And if I do that daily is one size better then another ?
DRD says
Good question. As long as you are reserving enough roaches to (eventually) replace the productive adults you currently have, the colony should in theory be stable over time. But there are so many unknown variables that giving you a precise number to feed off is impossible.
The best thing to do is get a feel for how the nymphs in your colony do over time – meaning how healthy they are as evidenced by how fast they grow, how many survive vs. die, etc – and feed off what you think you can afford to lose given what you see. On a basic level, to sustain your colony at its current capacity you only need one female nymph to live to adulthood for each adult female you currently have. But then there are those unknown variables. Not every nymph survives to adulthood. Not every adult live a full, productive life. You can’t predict these things in advance, but if you have an idea how the roaches in your colony are doing from week to week, month to month, you can make an estimate how productive they will be going forward and how many roaches you can feed off without affecting colony productivity.
Amy R. says
Hi. New to breeding. Picked up 9 appealingly pregnant females and 3 male roaches to start my colony for feeder purposes. I’ve read through your posts, and it appears I may have underdone my roach count. I brought them home today and set them up in a 30 gallon taped tub with 4 egg crates, cricket water, greens, and calcium. Tub is set up on a thermostat with blankets. I’m trying to establish a solid food source for my 2 beardies who are eating me out of house and home.
From everything I’ve read, I’m off to a solid foundation, but when you say “newly emerged females”, are you referring to them at birth, or once they have undergone their final molt?
DRD says
Newly-emerged adult females are ones that have just turned from nymph to adult. We distinguish the newly-emerged females from existing breeders because existing breeders come from established breeding colonies, and there is no way to know their age or history. They could be midway through their breeding life, or they could be at the end of it.
With newly-emerged adult female Dubia, you know that they have their entire reproductive life ahead of them. That’s why we offer them. Alternatively, existing breeders are usually already pregnant (whereas newly-emerged females are obviously not) so there is a bit of a tradeoff with each of these roaches.
Moka says
I ordered 25 Minis a few weeks ago to feed a jumping spider I found. I did not have the heart to throw it out in the snow or leave it inside to become a cat toy. Anyways, the spider ate only one or two roaches and then went into hibernation. I plan to raise up the remaining roaches and let them just live out their lives. My problem is I don’t want a colony or breeding at all. Can I separate the females and males and keep them in different enclosures?
DRD says
Yes, you can do that. For simplicity, the easiest thing to do is remove either males or females as they morph into adults. The females tend to not mate immediately, so you’re probably safe for at least a few days.
To be absolutely safe, you would have to sex them as nymphs. It’s easy to do, but you have to know what to look for.
An extra body segment is present on males, and you can see it at their rear from their underside. Females do not have this extra segment. It becomes easier to see as they grow larger, so you have some time to see if you can find it. Take a look at their bellies when they are about 1 inch or larger. You should see that some have that extra body segment while others do not. Males have it. Females do not.
Nate says
If I start with 20 female Dubia, how can I make them breed as fast as possible so they produce enough nymphs for 2 bearded dragons?
DRD says
Regarding your question, there are many factors at play – not the least of which is the appetite of your bearded dragons.
You will find some answers to your question here on this page, but you can also read about breeding Dubia roaches, which will help you learn what you need to do to get to where you want to be, which sounds like a supply of feeder roaches for your bearded dragons.
Vaughan R. says
Just a question about numbers of Dubias eventually. To get a general overall population count of colonies, I would assume you don’t do a physical count. Do you have different size screens to separate the nymphs, juveniles and adults and then count. To count all sizes in the totes would be a weekend task if you already have around 10-12000.
Kind regards.
DRD says
Hi. It’s a good question, but it gets into trade secrets that we wouldn’t want to give away to the competition because, as you rightly imagine, sorting Dubia roaches can be a lengthy process. There are probably many different ways to sort, count, and track colony production, and screens of varying size is certainly a popular one. Hope that helps, at least a little.
Niels says
Hello,
what colony size do I need to feed about 500 roaches to my animals per day ? (chickens etc).
Thanks
Niels
DRD says
The calculation is a bit complicated because there are a lot of variables, and an important one is missing, which is the size roach you want to feed your chickens.
Very roughly…for a supply of 500 newborn Dubia roaches per day, you need 25 females to give birth each day. Assuming a six week cycle, this would require 1,000 females. Add 200 males for a 5:1 female to male ratio and you get 1,300 roaches.
This is a very rough estimate. Many things can affect Dubia roach reproduction. These include temperature, humidity, crowding, food, and general colony stress. And of course, the number of Dubia roaches required for x nymphs daily also depends on what size roaches your chickens eat. Insects die at every age and for many reasons, so the larger roaches your chickens eat, the more you’d have to increase the number of breeding females (and males) to make up for the loss – the rate of which again depends on colony conditions and the stressors mentioned above.
David N. says
I’m considering starting a cockroach colony myself I found this very informative. I plan on reading you’re breeding tips and guides here very soon thank you!
Efrain M. says
I want to start a roach colony. I have a 3 month old bearded dragon who loves these roaches. Will I run short if I start 20 females and 10 males?
DRD says
Yes.
Dubia roaches are fairly slow to reproduce. Your 20 females will produce nymphs under ideal conditions, but they’ll take a while to grow out. It may take four to six weeks for newborn nymphs to reach 1/2-inch, for example.
20 females can help supplement your bearded dragon’s Dubia roach habit, but they won’t support it completely.
Vaughan R. says
Hi, this is the most informative post I have read on insect breeding in general. I started with 500 Dubias close to adult size in August last year, with the 1st nymphs arriving beginning Dec. I have since split the colony into 2 tubs (80lt approx 21 gal ea). A mix & match of adults & nymphs into each tub. I am planning to leave them until Dec but will obviously split them into more tubs as new nymphs arrive. July/Aug should see the Dec born nymphs producing their own offspring. At the end of this year I will start using them as feeders for my reptiles. By then there should be quite a large colony. I started to breed Mealworms, Superworms, Crickets & Turkistan roaches as well in the latter part of 2018, with the Turkistans being the last to arrive. My aim is to open a reptile rescue center here on the East Rand. (Eastern part of Johannesburg, South Africa). I currently have 36 reptiles which also begun from zero 6 months ago, but this number will probably reach around 100 by year end.
Thank you once again for sharing your knowledge & expertise with the people whom are eager to do things correctly with regards to breeding insects, especially Dubia roaches.
Kind regards
Vaughan
Tanya L. says
Hello, you’re site has been very helpful to me – but I wanted to ask what to do if the developing babies reach adulthood and you end up with far too many adult males?
Many thanks
DRD says
You could feed them off to your animals.
Joe L. says
My roaches haven’t made any more and they have been together for 4 months. The ratio is 10 females and 2 males. What am I supposed to do?
DRD says
One or several things could be causing your breeding issues. There is no way to know what it could be without knowing more about the colony and your situation.
To start diagnosing the problem, read our article about Dubia roach breeding. It’s a comprehensive breeding guide that you may find helpful.
After that, check out our post about Dubia roach breeding problems. It’s an in-depth guide designed to help diagnose and fix Dubia roach breeding problems.
Jason B. says
I have an 18 gallon tote that currently consists of 60 females and 10 males, plus an unknown number of nymphs. Probably 50 or so. I would like to add more adults to the colony, but how many is too many in a tote that size?
DRD says
The key is the usable surface area of whatever harborage you use. A (very) general rule for egg crates, for example, is 50-100 adult Dubia roaches (or comparably sized nymphs) per egg crate. This number includes front and back. For example, if you have six egg crates in your 18-gallon tote, that would translate to 600 adult Dubia or 600 (adults + comparably-sized nymphs).
With this density, you may have to remove newborn nymphs as they arrive, or they can become too crowded. With fewer roaches — say 50 to 75 adults per egg crate – you can separate nymphs from adults less frequently.
Jak R. says
We are new leopard gecko owners, and currently have 10 adults and sub adults. They vary in size from 45g all the way up to 73g. I have changed them over to srtictly dubias with only a cricket or mealworm when my local pet store is out of roaches. We are wanting to start a new breeding colony to feed all of our geckos plus one juvenile Savannah Monitor. The geckos are on a every other day feeding schedule, some taking only one medium to large roach to the biggest one taking 5 large on occasion. Ive got all the supplies to start my colony and have researched for hours on how many to start with. I found your guides to be one of the most informative, and thought maybe you could give me a good guestimate on what to start with. I was thinking 25 adult females, 7 adult males, and maybe 100 mixed size roaches if it doesnt get too expensive, keeping in mind I still will have to supply seperate feeder roaches to my reptiles until it gets established. Any advice on a good number to start? I would appreciate it so much. Thanks!*!
DRD says
Glad to hear you found our information helpful!
So your question, if I understand it correctly, brings up issues relating to Dubia cost vs. productivity assuming a starter colony that includes not just adults, but also nymphs of various stages. I think that could all be worked out, but the answer is still going to depend on both time and cost. In other words, there will always be sacrifice of one or the other, and where you ultimately decide to settle takes both into account. I don’t think there will be a single point identified as “the fastest and the cheapest”.
And, key variables such as growth rate, adult productivity, etc. will vary from set-up to set-up. Temperature, humidity, light & dark, nutrition, and more probably have a big enough impact that the results are only relevant to the environment tested. They may become meaningless as you move from one environment to another – from one set-up to another – given the variability that I know is out there.
Having said that, my sense is that rather than females, males, and mixed sizes, I might recommend getting as many females as you can, then adding males in a F:M ratio of anywhere from 5:1 to 7:1. This assumes that the 100 mixed size Dubia you mention are intended as breeders once they mature rather than feeders, and that you would feed your animals with separate roaches from the pet store you mention. Both strategies will work (adults+nymphs, adults-only), but I think focusing more on breeding females will probably get you where you want to be the fastest…unless you got really lucky and picked the right mix of nymphs at the right price that would result in the largest colony in X time. But I think the odds of hitting the “best” mix for you, if it even exists, is very low.
So your idea brings up another issue, which is that in our experience, mixed Dubia colonies tend to do better than those containing roaches separated by stage – in this case colonies of adults vs. adults & nymphs. However, this benefit is not enough to make buying 25 females and 100 nymphs worthwhile. Dubia will breed just fine in adult-only colonies, so I would recommend shifting your budget to something like 90% females and males and 10% nymphs. This seems more in line from a (potential) benefit/cost perspective. Of course, regarding this particular issue, you could go with all adult females & males and be just fine. The 10% nymph idea is a nod to your idea as well as the notion that there may be a benefit…and it keeps that benefit in perspective. In other words, in our experience it does exist, but it’s probably pretty small.
And…it keeps in perspective the risk/reward of shooting for that “right mix” of nymphs that will result in the most Dubia over time. You could even try 80% f/m and 20% nymphs. This seems like a reasonable range given what I know about the potential benefits you might see from it.
Hope this helps.
Jason B. says
I haven’t been using the cut out holes with screen for ventilation. Instead, I used my drill with an extremely small bit size and drilled lots of holes on top and around the upper sides. Is this adequate ventilation?
DRD says
The goal is to provide enough airflow and to do so without creating new problems in the process. As long as you achieve that, you’re fine. The method is less important than the result.
As for whether or not lots of little holes provide adequate ventilation, we can’t say. It certainly could, but every situation is different, so test it out and see. If the roaches do well, moisture doesn’t build up, and the air doesn’t stagnate, your method is OK.
David F. says
By the way the females are looking very large as if maybe they are pregnant. Lets just hope for that :)
David F. says
I am trying to breed my Dubia’s. currently I have 6 adult females and 6 adult males in the same large container. They have been in there for at least 3 months now and I was wondering if I have to many of males in there, Should I continue with that ratio of roaches in the same container? The container is a 25 gallon black container with plenty of ventilation and a heating pad under the container. The colony sits in my closet where it is dark and very warm. Plenty of food and water crystals. Am I doing this correct or can you give me some advice?
Thanks
David
DRD says
David – take a look at our Dubia roach breeding guide and articles on population density, breeding, etc. 90 days is enough time for the colony to start producing offspring, assuming conditions are adequate. If problems exist, they are more likely something like temperature than too many males. Our Dubia Roach Breeding Troubleshooter can provide information about specific problems in your colony that may hinder breeding.
With only six females in your colony, you don’t need six males. One would be enough if you knew it was healthy and fertile. While six males could cause stress, it’s unlikely to be enough stress to hinder breeding.
Females do get larger when carrying eggs. Their bodies will elongate to accommodate the eggs, so maybe there’s no problem at all.