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 --- Short Guide to Breeding Mealworms ---

I see so many questions on here about breeding mealworms; and though there are many websites online that explain the process, I thought I’d make an instructional guide myself. I’d like to mention that there are several ways of doing pretty much anything, and there’s no exception when it comes to breeding mealworms. This is the way I’ve done it, and has worked for me. Others may wish to change enclosure sizes, types, etc. which of course is ok.

Mealworms are the larvae stage of the Tenebrio Molitor, the Darkling Beetle. It isn’t the mealworm itself that breeds, it’s the Darkling Beetle. There are four stages to a Tenebrio Molitor’s life. Those stages are of course, first, the egg. These then hatch into very tiny mealworms. These mealworms grow to be about an inch in a month or two. These then pupate, which look like alien-type curled up mealworms. Once they emerge from the pupae, they’re at the final stage of life. The stage that does the breeding, which is the beetle. The mealworm’s life from the day the egg is laid to its death can be approximately 5 months or so.

In order to start a colony, you’ll need the following items.

2-3 medium-large (15+ qt.) plastic containers/shoe boxes - Wal-Mart, $1-$6 depending on size.
1 small plastic container/shoe box (5 qt.) - Wal-Mart, $1
Wheat bran - Feed store, $10 for 20 lb. bag
500+ mealworms - Online or pet store (Petco 500 for $6.99)
Fruit or vegetable for water source - Potato, carrot, apple, etc...

All containers should be cleaned and washed prior to starting a colony as you don’t know exactly where it’s been. Once this is done, place about 2 inches of bedding in one of the bigger containers. This is where you place your mealworms. You can of course start with a smaller amount, and use smaller containers, but this is what I use. You can use several smaller boxes for groups of smaller colonies, or you may use several big boxes for one big colony. Your choice. I’ve also heard others that don’t move the different stages into different boxes and just breed in one large container. I move mine just to be on the safe side.

In a bed of bran, the mealworms grow and molt very quickly. Depending on the size of the mealworms you’ve purchased, it can take from 1 week to a month or so for your mealworms to pupate. This is why it’s suggested you purchase the largest mealworm size available. Do not confuse regular (Tenebrio Molitor) mealworms with Superworms or Giant Mealworms. Giant Mealworms have been fed a growth hormone that sterilizes them, leaving them infertile. Most say that they don’t pupate at all, which I find untrue as I’ve had many pupate on me, though I have yet to see any hatching mealworms from that colony. Though they look similar, Superworms are NOT Tenebrio Molitor and are a completely different species (Zophobas Morio) than the mealworms we’re breeding here.

You may place carrots, potatoes, apples or your choice of moisture on top of the bedding. If there is not enough moisture in the bin, they may cannibalize each other. But, too much moisture and the mealworms may die from molding. It may take trial and error to find out how much to use. I place about 3-4 1 1/2 inch carrots in mine and change it every 3 days once they’ve dried out. I don’t believe apples work as great as it molds VERY quickly.

Once the mealworms pupate, they can be removed from this container into a smaller container with only an inch or less of bran. I use a 5 qt. shoe box, but any other would work. They don’t move much if at all at this stage, so size of the box doesn’t really matter. They’ll stay in the pupae stage for approximately 2 weeks. I don’t put any sort of moisture in this bin as once they turn into beetles, I remove them quickly into the next container.

Once they turn into beetles, it is best to move them quickly to the other large container, which is their breeding container. If left with the pupae, they may cannibalize and kill the pupae. In this container, there should be 2" or so of bran. They will start breeding in the first few days once they’ve become beetles, and will continue until they die. I haven’t quite noticed when and how often they die, but I’ve heard ranges from 6 weeks, all the way up to 16 weeks. Many do agree though that a female will lay between 200-500 or more eggs in her lifetime. Given the big range of its lifetime, I’d say that’s an approximate 100 eggs you should get from one female every month. This container should be supplied with moisture as well. I also put about 3-4 1 1/2" pieces of carrot in this bin.

I personally move the beetles every 2-3 weeks into a new container with new bran to avoid the beetles eating the eggs. I believe this gives you a better rate of surviving mealworms. The old bedding I then put into a 16 qt. container to grow out. You can put it in the same container as the larger mealworms but I like to keep these babies separate. Once they grow a bit, I then put them with the adults. Again, you don’t have to do this. This is just what I do.

In a month or so, you’ll start noticing a whitish/light grey powdery substance in your mealworm bins. This is frass (mealworm poop). Once there is a noticably larger amount of frass than bedding, they bedding should be changed. This isn’t necessary in the breeding bin, as this is always changed and put aside every 2-3 weeks anyway.

With a starting amount of 500-1000, you should yield a good amount of beetles to start with a good size colony.

The following are pictures from my own personal colony.

Although they may seem large in this picture, these baby mealworms are actually VERY hard to spot. Though once your eye is trained to know what to look for, it can be easier. These are probably a week or two old. I was unable to capture a new hatched mealworm as they are about half the size of these and very hard to focus on.

This is a week or two old mealworm.

These are the beetles.

These are the bins I started with. I then expanded into another colony, and am now in the process of upgrading to larger bins.

09/17/08  01:18pm


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  Message To: Slove1106   In reference to Message Id: 1861766

 --- Short Guide to Breeding Mealworms ---

Hey, nice job! I use oatmeal, just easier for me to get. I was noticing that I am not getting so many babies lately, but then again I have left the beetles in there for a long time. My son had fed most of the beetles to our dragon, so I pretty much am starting over. So do you know for a fact that the beetles actually do eat the eggs????

09/29/08  12:00pm


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  Message To: Clouddancer22   In reference to Message Id: 1870655

 --- Short Guide to Breeding Mealworms ---

Thanks. :) And to answer the question, I honestly don’t know that for sure. That’s actually what I’ve read happens. But I can tell you it’s probably true if they’re hungry enough as I have seen them cannibalize each other. So if they do eat each other, I’d guess they wouldn’t have a problem eating eggs either. There’s been times when my carrots have gone pretty dry and I didn’t get another carrot in quick enough and I’d find a couple dead beetles that are hollowed out... Now unless they just dried up, then I’m almost positive they were actually nibbled on by the others...

09/29/08  05:59pm


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  Message To: Slove1106   In reference to Message Id: 1870875

 --- Short Guide to Breeding Mealworms ---

I actually caught them canabalizing another beetle!! I KNOW for a fact they do that. I am thinking that when a beetle slows down, ready to die, the others jump on him and eat him. I have been suspecting that for a while, and I SAW it this time! I always have plenty of potatoes and carrots in there, but it doesn’t matter, they will always eat the dieing ones which why I very rarely find a dead one in there, but I often find left over parts, lol.

I was just wondering if they ate the eggs b/c they just wanted to, or resort to them if they don’t have enough moisture? I know my male crx will only eat the eggs if there is not enough veggies in there, which is why I am carefull about that. But I can SEE the crx eggs, and I cannot see the mealie eggs.

Just wondering . . .

10/18/08  12:05am


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  Message To: Clouddancer22   In reference to Message Id: 1882790

 --- Short Guide to Breeding Mealworms ---

Made an actual guide with lots of pics. Link

12/16/08  11:20am


Nick and his geckos
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  Message To: SCGeckos   In reference to Message Id: 1915327

 --- Short Guide to Breeding Meal worms ---

i have this huge bowl like sifter, and i shake it to screen out the meal worms from there poop, works like a charm, if you have as many as i do then its save hours.

01/05/09  11:03pm


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  Message To: Nick and his geckos   In reference to Message Id: 1927146

 --- Short Guide to Breeding Meal worms ---

Where did you buy your sifter, I spent 8 hrs last week slowly shifting threw different stages of meal worms.

02/14/09  02:48pm


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  Message To: Ratqwen   In reference to Message Id: 1952700

 --- Short Guide to Breeding Meal worms ---

Can the beetles climb the walls of the rubbermaid tubs? Mine have a few air holes about a 1/4 in diameter and then just the lid on...If they can climb how do I keep them and keep air flow going for them?

06/24/09  10:25am


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  Message To: Herpsarelife   In reference to Message Id: 2027999

 --- Short Guide to Breeding Meal worms ---

lol one of the bettles looks like an almond

05/20/10  09:48pm


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  Message To: Waldorepticzone   In reference to Message Id: 2149201

 --- Short Guide to Breeding Meal worms ---


lol one of the bettles looks like an almond

Hah it kinda does!

I really wish this forum were more active. This is a great guide. Following this guide (well, the more detailed one that she had on her website that is no longer there) taught me everything I needed to know.

Since this is the shorter version, I would like to add a few tips.

Oatmeal and other larger beddings are nice and all, but if you want to save yourself a million years of cleaning and hand-picking mealworms out of the beetles, use wheat bran. The smallest-holed sifter, or the lid of one of these if you happen to have one ( link ) are great for sifting out the frass in mealworm containers without wasting the good bran or smaller mealworms. Some very small mealworms can get through the holes, but usually when they are small enough to go through even that small of a screen, they don’t really need their cage cleaned anyway.

When it comes to separating eggs/baby mealworms from beetles, sifting the beetles with a standard 10 gallon tank screen lid is easy. The standard 10 gallon tank screens have larger holes so that all of the bedding, eggs, and baby mealworms can be sifted out, leaving just the beetles behind.

Carrots are better than anything. It doesn’t mold easily or make the bedding too moist and the mealworms LOVE them. Carrots are more nutritious than potatoes also.

Fora small colony of mealworms and beetles, (fits up to 3,000 large mealworms comfortably in one drawer) plastic 3-drawer units are great. I usually put mealworms in the top drawer, pupae in the middle, and beetles on the bottom. There is no need to add air-holes because there is plenty of ventilation. Mealworms and beetles cannot escape from them.

Walmart has a great deal for a larger version of the 3-drawer units. $30.00 for a set of 3 of these larger units, that’s 9 individual tubs!

07/09/10  05:33am


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  Message To: Reflex   In reference to Message Id: 2161281

 --- Short Guide to Breeding Meal worms ---


- If you live near a WINCO or similar store, check there for wheat bran. WINCO sells them for only $0.36/lb in the bulk foods section.
- The more mealworms you start out with, the faster your colony will become large. Try to get mealworms from someone local or a feeder breeder online. I speak from several experiences that pet store refrigerated mealworms tend to die wayyyy fast when trying to get them to pupate. You’ll only have a fraction of surviving worms left by the time they start pupating. Finding worms that have never been in the fridge is probably a better option.

- I haven’t read through this mealworm guide in quite awhile, but one tip to getting a colony of large mealworms to pupate is to remove their water source for a day and a half or so. For some reason, doing so produces a lot of pupae. Make sure not to take out the water source for too long or else they will start to cannibalize one another.
- Placing their container in a closet or dark area will help also.

- Temps of about 80 degrees will make mealworms start to grow crazy fast. Perfect for if you have a room in your house that stays warm in the summer.
- Adding a heat source to the back of the cage seems to create mealworms that are uneven in size despite hatching at about the same time.

07/09/10  05:47am

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