How to Raise Mealworms

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Mealworms are the larvae of mealworm beetles and are used as a food source for many different exotic pets. Reptiles, amphibians, sugar gliders, skunks, chickens, hedgehogs, and other animals consider various sizes of mealworms as part of their regular diet, but they don't always contain the nutritional components these pets need because they are often sitting in a store without food for extended periods of time. Additionally, the cost of regularly purchasing live food sources, such as mealworms, can become inconvenient and expensive to pet owners. Thankfully, raising your own mealworms is easy to do and can help you ensure your pet is receiving nutrient-dense food.

Project Overview

Working Time: 15 minutes

Total Time: 2 months

Yield: Hundreds of mealworms

Skill Level: Beginner

Estimated Cost: $20

Before You Begin

In order to raise mealworms, you'll need a little bit of space dedicated to housing your mealworm colony. This space should never get too cold, so do not keep your mealworm colony in a garage or basement that will get cold in the winter.

Next, supplies and the adult mealworms will need to be purchased, and a couple of months will need to go by before you can start feeding your pet your homegrown mealworms. This means that you will still need to purchase mealworms at the store for at least two months after you set up your mealworm breeding enclosure. You will need this amount of time for your mealworms to grow.

This project won't take up much of your time to start, but once it is set up, you'll need to be patient. If you only need a few mealworms for a short period of time, raising mealworms probably isn't necessary. But if you expect to need mealworms for at least a year, the sooner you start this project, the sooner you'll have nutritious, convenient food for your pet on an ongoing basis.

Materials You'll Need

It's easy to start raising mealworms for your pet. All you need are a few inexpensive items!

What You'll Need

  • Small plastic or glass enclosure with a vented lid
  • Bran or oats
  • One or two dozen adult mealworms
  • A raw potato cut in half

For your mealworm colony container, a shoe storage bin with holes poked in the lid, a small aquarium with a screen top, or a plastic Penn-Plax container with a vented lid are all great options. You'll just want to make sure that the container you choose will allow light to go through it (i.e. is clear or translucent), has a solid bottom to prevent the mealworms from escaping, and has holes in the lid to allow for ventilation. Any store-bought bran or oats are good for the substrate and a raw potato cut in half will provide food and water for your mealworms.

When You Can Feed Mealworms After Growth

Once you've placed your store-bought, adult mealworms into the new enclosure you set-up for them, you'll have to wait at least two months for your mealworms to go through one life cycle. Because the mealworms you buy at a store are already in the larval stage, they should pupate in about three weeks. Two weeks after they pupate, the mealworm beetles should emerge. These beetles will lay very small eggs which are difficult to see in the substrate. When these eggs hatch, the new larvae are also very small so don't expect to be able to watch this process very closely but you will see the mealworm beetles die while the larvae grow. This life cycle will continue to repeat with any mealworms you don't feed to your pet but after just one life cycle, your mealworm colony should be well established and you can start using it to feed your exotic pet.

Mealworm Sizes

A mealworm is the larval stage of the mealworm beetle (Tenebrio molitor), so despite common misconception, there are not different sizes of mealworms unless you feed a juvenile hormone to your worms. This is how the giant mealworm is grown. There are, however, different ages of larvae; emerging larvae are going to be smaller than larvae that are about to pupate. A mealworm larva will molt (just like tarantulas and hermit crabs) between nine and 20 times before it pupates, so after each molt it will grow ever so slightly, but it won't naturally grow to be longer than about an inch without feeding it juvenile hormones. If your pet needs larger worms, superworms (Zophobas morio) may be a good alternative to raise. They go through the same life cycle, so the process to raise superworms is the same as it is for raising mealworms.

Maintaining Your Mealworm Colony

Once you start feeding the mealworms from your colony to your pet, you can offer a commercial diet for gut-loading or a home-made variety of vegetables and fruits such as carrots, orange slices, and leafy greens to the colony to gut load them. This will increase the nutritional value and change fix the low Ca: high P ratio mealworms, crickets, or any other type of bug you purchase online or in-person. Be sure to remove any uneaten food before it begins to mold or rot though; this can cause your mealworms to die.

Once you have a large supply of mealworms, the dirty substrate can be filtered out and the mealworms can be saved to put in the clean substrate. If you filter the substrate before your colony is well established, you are likely to filter out all the eggs or new larvae and the life cycle will be interrupted. Provide at least one or two inches of substrate so that your mealworms can burrow so you will need to add more bran or oats as necessary to maintain this level. You may also need to completely change out the substrate on occasion to keep it clean and fresh as well as wipe down the container.

Does Temperature Matter?

If you are worried about your colony staying warm enough due to cold weather or air conditioning, place a heating pad under the container to keep it warm. If your mealworms get too cold, they will stop growing, and you also won't get any more new worms. If you no longer see new mealworms, make sure the container isn't too cold.

If you have too many mealworms, simply place the whole container in the fridge to temporarily stop their development. Rewarm it to room temperature when you need them to continue to reproduce.