Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle. They go through four life stages: egg, worm, pupa, and beetle. Worms typically measure about 2.5 cm or more, whereas beetles are generally between 1.25 and 1.8 cm in length.
So, they can be fed to reptiles, poultry, birds, rodents and lots of other kinds of pets. They are not hard to keep and breed. I would like to start by saying most of this is all personal choice. There is no right or wrong way to do it, if it works for you, go with it. But I have learned a lot of what I know on websites and YouTube, both are excellent ways to learn about keeping mealworms. The first thing you need is a smooth sided plastic container or even a fish tank. Most people say to get one of those drawer systems.
I personally like the single type of containers. Dish pans from the Dollar Tree or even kitty litter pans. Mealworms do not climb much or fly, so they don't need a top of them, unless you want to stack them. That is up to you. Once you decide, make sure if you do use lids, to put air holes in them, for air and for humidity. I used a metal hanger and a heat source to just poke holes in to the plastic.
I put holes in the sides and in the tops, just so they have plenty of air. For the drawer system, you may just need to leave the drawers open a little bit for air. Once you have gotten your container, you will now have to choose a bedding/substrate. Mealworms eat their bedding, the beetles lay eggs in it, so it needs to be some sort of grain. You can use many different kinds of grain beddings. The most popular ones.
Rolled oats, either the quick or old fashioned, the difference is the size of the oats. Wheat bran is very cheap at most feed stores. Even cereal, ran through a food processor can be a great beddings. Some other popular grain items would be cornmeal (not mix), chicken starter, or any mixture of these would be fine for all life stages of the meal worm. Try them out, see which you would rather use and stick with it. So now we have our container, and our bedding. Now we need some mealworms! You can buy them from a friend, from a pet store, from a mealworm company like Rainbow Mealworms. It is up to you. Now you can buy the starter kit from Northeastworms
Now you will add 1-2 inches of bedding to your container. I use a little deeper for beetles, just because they like to dig into the bedding.
Mealworms do not drink water. Instead they get their water from food. The most common foods are raw potatoes, carrots or celery. Some fruits are OK, but they can draw flies or ants, so you have to be sure to get them out before they mold or rot. Just cut them up and place them on the top of your bedding. Usually skin down, so it doesn't get your bedding wet and cause mold or mites.
You can also add things for your worms to hide in or under! Paper towel rollers, toilet tissue rollers, paper egg trays. They also like paper towels, but they get into the layers and it is hard to get them out!
Be sure to change your moisture food out every other day or so. The potatoes and carrots can stay in longer. They seem to like the older veggies to nest it. But don't let it mold. Just watch out when you go to throw the old food out, it can have worms in it. Also, they love bread! Hard bread, they tunnel through.
It will take a week or 2 for the mealworms to turn into pupa. Depends on your temperature. They like to be 75-85 degrees. Pupa is a cocoon type state. They do not need bedding, food or water. You can put them in a little holding container, in a week or 2 they change into beetles.
New pupa are almost white, as they age and get ready to come out, they turn tan-ish brown and you can see the eyes and legs more. I find that when my mealworms stop moving around, and lay on top of the bedding, they are going to change into pupa. They kind of gather in the corner and just lay there, not eating or moving much.
The beetles come out white tan color. Then turn red, then black. Once they turn black, they are ready to make you some babies! They lay eggs that you cannot see. They do lay them on everything in the container, so don't throw away anything for a while. After 2-6 weeks, you should be able to see bedding moving if you pick it up and watch it. A female beetle can lay 500 eggs in her life time!
After 2-4 weeks, or once I see babies, I move my beetles out, take the bedding and put it in a brand new container and give the beetles new bedding in their container and let them start all over. I set the old bedding aside, putting some moisture food in it and let the eggs hatch and the baby worms grow. This is the part that people get upset about, it takes time, so you cannot speed it up, they will appear when they do, just wait! If you have beetles, you HAVE eggs!
The process starts all over, the mealworms grow and grow, shed their skins, and BAM! They start turning into pupa before you know it!! It really is that easy. They are just bugs, don't over think it too much! A few things that you might want to do, either freeze or bake your bedding to kill grain mites. You can do both if you want. Just make sure the bedding is at room temp before adding your worms. 300 degrees for 30 minutes is good, or store in your freezer until you need it. Or 3-4 minutes on high in the microwave will do it, also. When the mealworms/beetles eat, they poop what is called frass. It is a very fine dust. To save on bedding, you can sift it with a kitchen colander or strainer.
Different sizes for different size bedding and worms. I found an extra fine sifter at walmart, it was $9, but only frass gets through it! The others I just went to Dollar Tree (everything a dollar!) Also 2nd hand shops is a great place to shop for worm containers and sifters! Some people say that mealworms like the dark, but I don't find they care either way. I have them in my spare bathroom, and light doesn't seem to bother them. Superworms on the other hand run when I turn the light on! I also found that if you buy your first mealworms from a pet store that a lot of the pupa will come out deformed. It is OK, though! I got my first ones at Petco, and probably half of them were deformed. Looks like half pupa and half beetle. But my first generation did not have as many, it was actually just a few did, which is normal.