where to grow mealworms in how to grow mealworms?
My mealworm bins are inside the house in the heated basement. The basement has an average temperature of about 22°C or 71,6°F and it’s relatively dry.
Under normal, wild conditions, the mealworm beetle and the mealworms live in a relatively cold system in decayed wood or in grain barns. In these barns, they can be real pests.
Although the common situation is quite cold, it’s best to keep the mealworms in a room where the temperature is above room temperature to let them grow faster and digest more readily. The best temperature is around 25°C or 77°F but as I grow composting worms too, I keep the temperature at about 22°C or 71,6°F.
So, keeping the critters in a bedding of wheat bran with some pieces of fruit or vegetables as a source of moisture and keeping them at least at room temperature, is more than enough to grow the critters without any problem.
the four phases of the mealworm beetle
The four different phases of the mealworm beetles have to be separated into different bins. So what are these four different phases?
The different phases are explained for a temperature of about 25°C or 77°F.
The first phase is the egg. This phase takes about 2 weeks. The eggs are about 1,5 mm long or 0,06 inch long. They are white and sticky so they stick to the bedding quite easily. This phase is a really weak phase and a dangerous phase because the females that lay the eggs are in need of lots of proteins to produce those eggs. As every moving phase of mealworms is very cannibalistic, it’s very much possible that one female eats the eggs of another female to produce her own eggs. I personally make sure the critters have some chicken feed to get their proteins from, to avoid most of the cannibalistic traits.
The female beetle can lay about 150 to 200 eggs in a period of several months. As these eggs are sticky, they get a good camouflage by sticking to the bedding. Although the camouflage works, it’s always good to give the beetles some toilet paper rolls and some pieces of cardboard to lay their eggs under.
The mealworm itself
The mealworm or the larva is the actual object that’s part of the trade amongst humans and that’s eaten by a lot of animals and some humans.
The larva starts as a really small animal of about 1 millimeter long. It systematically molts and grows in different steps until it reaches about 4 cm long or 1,57 inches long. The mealworm can molt up to 20 times before it reaches the right length to turn in to a pupa.
The growth of the larva goes in different steps because the critters can only grow in the short period where they have just thrown off their former skin. Once the chitin skin has hardened again the mealworm stops growing until it sheds it’s skin again.
Shedding the skin is visible in the bin because of two things. First of all, after a couple of days, we’ll find a lot of empty skins in the bin. Second of all, the new skin of a mealworm is white, so we’ll see a lot of white mealworms that turn darker after some time when the skin hardens again.
The pupae of the mealworm beetles
The pupa forms when the mealworm has reached an average length of 4 cm. In this phase, it sheds it’s skin and changes its appearance. Now it already looks like a beetle but it is a kind of cocoon.
In this phase, the critters are quite defenseless as they can only wiggle their tale to avoid being eaten. So, the first time you hold a mealworm pupa in your hands, don’t be shocked when you see it wiggle around. As these pupae are almost defenseless it’s better to keep them in a separate bin where they are safe from predators.
The pupa needs about two weeks to develop into a real moving beetle.
When the pupae turn into real beetles, it’s best to remove them from the pupa bin and place them in the next bin. This way the mealworm beetles don’t start munching on the other pupae in the bin. I personally don’t do this step anymore because I have seen that there’s no cannibalism when the critters have enough protein and moisture in the bin. But just to be sure, until you have found the right amounts, it’s good to split them up.
The mealworm beetle
After the third phase, we finally go over to the final stage, the adult beetles. In this phase, we have creepy crawly bugs and some flying beetles who will make sure there’s the next generation. The first two weeks of their existence the female beetles can’t lay any eggs yet. After those two weeks, the egg production goes on until they die.
At first, we’ll see a white beetle. After some time it’ll turn golden brown and finally it’ll turn totally black.
The mealworm beetle is about 1 cm to 2 cm long ( 0,39 to 0,79 inch)
The lifespan of the beetles is about 3 to 4 months.
I personally don’t keep them that long around as the egg laying goes down tremendously after the second month.
Wheat bran consists of quite large flakes. These flakes are the bedding for the mealworms but also their food. Once the flakes are chewed through it turns into mealworm frass or mealworm poop. The poop consists of really small particles that go through a kitchen sift very easily. So cleaning out the bin consists of sifting through the bedding and setting the frass aside. If the bedding was used for the mealworms, you can easily use it as a good fertilizer for the plants. If the frass comes from a bin with beetles, put the frass aside for a couple of weeks to make sure you can sift out all of the small mealworms after a while.
To gather the young mealworms to the top of the layer, you can put a carrot or potato on top. The mealworms will congregate around the potato. That way, you can easily get them out of the frass.