Mealworms (Mealworm beetle, Tenebrio molitor, Darkling beetle.) are an easy to raise source of protein and nutrients to feed to people, chickens or lizards. They are easy to breed and raise and this breeder design helps make it even easier and tidier.
This is a design that was shared with me by a friend a while back. There are plenty of videos on YouTube showing similar designs with the only differences being the number of drawers which are either 3 or 4. We’ll even be making one ourselves soon.
There’s little waste and hardly anything that can go off in this breeder. Everything besides the plastic can be either composted or put straight onto the garden or, even better, fed to chickens.
A semi-automatic Mealworm breeding and harvesting thingy can be easily made from a set of plastic drawers from a ‘cheap’ shop and following these instructions.
Drill some ventilation holes on every side, near to the top of each drawer.
Cut the middle out of the bottom of the top drawer. Leave a couple of centimetres around the edges.
I cut too close to the edges and will be using soft mesh, so I put a plastic strip across the middle of the hole for a bit more support.
Place the mesh in the bottom of the drawer and either hot glue or silicon around the edges to hold it in position.
Place a couple of centimetres of bran or oats in the bottom of each drawer and replace the top one in the rack.
Put the egg carton and some of the vegetable slices in the top drawer.
How does it work?
‘So, how does it work now that I’ve made it’? You may ask.
The system works from the top drawer downwards in a cycle.
The top drawer is where the beetles go. They mate and burrow into the bran to lay their eggs at the bottom the drawer. With movement and time, these eggs and some recently hatched baby worms will drop through the mesh into the next level.
The second drawer is where the eggs hatch and the new larvae grow. Once you can easily see them, move them to the third drawer.
In the third drawer, the larvae get bigger and bigger. These are the “Mealworms” we are after. In a short period of time, these larvae will change into pupae. These you pick out and put in the fourth drawer.
The pupae hatch into adult beetles in the fourth drawer. These are picked out and put into the top drawer where the cycle repeats itself.
Mealworms eat the bran that they live in. The vegetable pieces only provide moisture for them to ‘drink’. Keep these changed at least weekly to prevent spoilage of the bran and mold.
You don’t need to put vegetable pieces in the bottom tray as the pupae don’t eat or drink. The beetles can last a fair while before they need moisture and you’ll pick them out before then. I put one piece in just in case I don’t get to do their weekly maintenance for some reason and one or two hatch out in the mean time.
The egg carton gives the beetles a place to hide and a place to climb on. I’m not sure why they need to climb though, I’ve just seen it mentioned in a few places.
There you go! You’re breeding Mealworms!
If you want more info, check out this post I wrote about a mealworm’s life.