Breeding
There are many tutorials online. I recommend doing your own research. This is only a very basic idea of what to do.
Mealworms are very easy to breed; they pretty much take care of it themselves if you meet their needs. At minimum, you can get a big, shallow tote, like one of the ones that is meant to go under a bed, add an inch of bedding, add your mealworms and then just leave them to it. They will grow, pupate, turn into beetles, breed, and lay eggs all on their own if you just keep their habitat the way they like it. You won’t get maximum production, but depending on your needs you’ll still get plenty of mealworms.
Mealworm Life Cycle
Mealworms pupate into pupae, which emerge into beetles, which mate and lay eggs, which hatch into tiny mealworms, which eventually grow up and pupate.
See more pupae information here: All About Pupae
Better Production
If you want higher levels of production, you will want a minimum of three containers, two large, one small. I personally use the plastic shoe boxes you can get at Walmart for $0.88 each and I use a lot of them. One of the containers you bought your mealworms in can be your small container.
- Container 1: Mealworms. This is your mealworm habitat. Keep them happy (see Basic Care).
- Container 2: A cup or a dish or any plastic container will do. When the mealworms pupate, put the pupae aside in this container so that 1, the mealworms won’t eat them, and 2, you can monitor their progress. **NOTE you can keep pupae in with the beetles with a “pupae bridge.” You can make one easily by turning a plastic container with a flat bottom upside down and setting the pupae on it. I can also sell you a nice laser-cut one, $5 - $20 depending on what size you want.
- Container 3: Your beetle habitat can be set up similarly to the mealworm habitat, they have the same basic needs. Beetles will need liquid in the form of vegetables, but not too much liquid, and the bedding should stay dry, same as mealworms. After the pupae have turned into beetles, put the new beetles in this container to live. They will start breeding after they’re a few days old.
Note: pupae are filled with liquid; the beetles, and to some extent the mealworms, will use them as a liquid source. That’s why they need to be kept separate.
Swapping Containers to Save Eggs
Beetles will eat their eggs, but if you're keeping up on giving them enough moisture-filled-foods, they aren't likely to eat enough eggs to matter. A lot of people who are trying to maximize production will separate their beetles from their egg-filled bedding every so often.
It is generally recommended you let new beetles stay in their initial container until you see babies. There are a few ways you can find babies -
- Take a spoonful of the bedding out and spread it on a paper towel or white piece of paper and look for little brown squiggles moving around
- Make a line in the bedding with your finger and see if it moves at all.
- Place a piece of carrot or other water source on the bedding and after a little while, pick it up and see if there are any babies on the other side
I would honestly suggest just waiting 1 month from your first beetle going into the box and calling it good. The eggs are nearly impossible to see, and it takes 1-2 months to see babies. Beetles will start mating and laying within a week of becoming beetles.
After you have eggs, you probably want to separate out your egg-filled bedding. There are two ways of doing this.
- The easiest is where the optional extra containers come in. Make yourself up a new beetle box and move the beetles to it. The old box is now a nursery.
- If you can't easily use the old box as a nusery, grab a new box (any plastic box will do at this point) to be a nursery. Separate out your beetles and dump the old bedding from box 1 into the new nursery box. You'll see stuff stuck to the bottom of box 1 - these are eggs! Don't scrape them off or you will likely kill them. Add new bedding to box 1 and return your beetles.
- Same as #2 except just add your old bedding into your mealworms box and call it good. This makes sifting frass harder, so I don't recommend it, but it's a valid option and will work.
- Don't worry about it at all and leave everything in the same box until the mealworms are big enough you can sift them out to join your other mealworms.
I like to swap beetle containers every week, but most people do it every 2 weeks or more.
The eggs hatch in approximately 2-3 weeks, but can take as much as a month or more. Baby mealworms took me about 5-6 months for them to age up to large mealworms.
Container Options
You can use any plastic tote, really. You just want something shallow that will fit where you want it to go.
Many people (myself included) buy a Sterilite 3-drawer container to get themselves started: Sterilite 3 Drawer Organizer
My primary box has been a simple plastic shoe box: Sterilite 6-Quart Storage Box
Eventually I bought a cheap 9-drawer tower and I’ve loved it, although I’m still using the shoe boxes for beetles and nursery boxes, I’m using the tower for all the mealworms. Seville Classics 10-Drawer Organizer
How many beetles in a container?
It depends on your goals. Maximum productivity will be at about 2 - 3.5 beetles per square inch of living space. You can go higher than that, and beetles have been shown to have better immune systems in higher densities, so it’s a tradeoff, because at over 6 beetles per square inch their individual egg production drops off significantly. That being said, if you have a lot of beetles in a container, you’re still going to get a lot of eggs, even if you aren’t getting the maximum eggs per beetle you might get giving them more space.
While I try to keep my beetles at around 3.5 beetles per square inch, many breeders go much higher, like 6-12 beetles per square inch.
A lot of people will increase the beetles’ living space with egg crates. The beetles will lay eggs on the egg crate, so I personally don’t do it but you can get a lot of surface area for the beetles in a small space that way.
Self-Sorting Beetle Bins
Rather than swap your beetles every once in a while, you can make a self-sorting bin with some window screen or some metal screen and two plastic boxes. I've made some and will eventually add my instructions, but for now you should be able to google "how to make a mealworm beetle self sorting bin" and find what you need if you want to make your own.
Beetle Flight?
The beetles generally don’t fly, but can.* I don’t keep my beetles covered, but you may want a loose cover on yours if you find your beetles start escaping. Generally, if they’re happy, they don’t try to fly away. Reevaluate if you’re taking good care of your beetles if they’re flying.
*I've watched my beetles attempt to fly and they don't get much farther than a little kid jumping off the couch while using a blanket as wings. While I've heard of several people discussing their beetles flying, I'm beginning to wonder about the accuracy of those stories. They open their elytra (the hard shell part), spread their wings, and go maybe a centimeter with a bit of a "bzzzz" sound.
Keeping Pupae Safe / Pupae Bridges
See information about pupae bridges/tables, and boats on my All About Pupae page.