What Do Mealworms Eat?

© iStock.com/MattiaATH

Written by Lex Basu

Updated: October 14, 2022

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Key Point

  • Mealworms make great food for small pets such as lizards, birds, chickens and fish.
  • They have been marked as safe for humans to eat.
  • Mealworms turn into darkling beetles. Both mealworms and darkling beetle are harmless in nature and their greatest offense is the foul smell they emanate.
  • Mealworms eat a variety of food, including vegetables, fruits, plants and grains, but they largely avoid onions and fruits from the citrus family.

Mealworms are small tan and brown worms that you may have seen outside near tree stumps or underneath leaves. In the wild mealworms are technically considered to be pests, but for pet owners they can very valuable. Many species of lizards, fish, and birds eat mealworms as a source of protein and fat. Chickens and other barnyard animals also enjoy mealworms. One of the most unusual facts about mealworms is that they are considered safe for humans to be used as a food source.

Once matured mealworms turn into darkling beetle, also known scientifically as ‘beetles tenebrionidae’, is a species of black colored large sized beetle that are completely harmless to humans. Their only defense is the mildly foul smell that they emanate. these beetles are scavengers and omnivores, mainly living on decomposing trees and other plants, leaves, other decaying animals carcass and fungi. The mainly live in the wild and make a good source of food for other animals, such as birds, rodents, spiders, lizards and other predatory insects.

With mealworms being a common meal for pets, you might be wondering what mealworms eat themselves. Let’s dig into their diet!

What Do Mealworms Eat
Mealworms eat decaying matter, animal waste, fungus, and grains.

What Are Mealworms?

Mealworms aren’t actually worms. They are the larval state of the darkling beetle. Beetles have four stages of development:

  • Egg
  • Larva
  • Pupa
  • Adult

When the darkling beetle lays an egg the egg takes anywhere from 4 to 20 days to hatch. What emerges from the egg is a mealworm. Mealworms will eat everything they can and then enter the pupa stage of development by cocooning themselves inside an exoskeleton. After a period of development the adult beetle will bust out of the exoskeleton and search for other beetles so that it can start laying eggs which will begin the whole process again. A single female darkling beetle can lay up to 500 eggs in her lifetime. That’s one of the reasons why there are so many mealworms.

During the larva stage of development the mealworm’s job is to find enough nutrients to sustain the pupa while it finishes growing. That’s why mealworms are prolific eaters and will eat just about anything.

What Do Wild Mealworms Eat?

In the wild mealworms will eat vegetables, decaying matter, leaves, animal waste, grains, and fruit.

The like to burrow into soil, decaying leaves, grain that’s rotting in a field, vegetable gardens, and places that have a lot of vegetation. Mealworms are omnivores, which means that they will eat all kinds of food. They will even eat other mealworms that have died. Mealworms like to eat apples and other fruits, potatoes, oats and grains, and birdseed. Wild mealworms also eat decaying matter like fungus, dead leaves, rotting fruits and vegetables, and rotting plants.

What Do Captive Mealworms Eat?

What do mealworms eat - a mealworm on a white background

Captive mealworms will eat vegetables,

dog food

, fruits, and oatmeals.


Mealworms can also be raised by hand in captivity. Why would anyone want to raise mealworms? A lot of people raise mealworms because mealworms are a great source of protein for pets like fish and lizards. Mealworms breed quickly and many people find that it’s more convenient to grow mealworms than to go to the pet store and buy them to use as food for their animals. Captive mealworms which are raised to be food for other animals eat whatever they are fed. They can survive on oatmeal, bran, fruits, vegetables, algae, and even dry cat or dog food. But mealworms prefer to eat fruits and vegetables like potatoes, apples, and carrots.

Raising Mealworms At Home

It’s very easy to grow mealworms at home. All you need to grow mealworms at home is a container that will hold them, like a plastic storage container with a lid. It doesn’t have to be large. Poke holes in the top of the container that will allow air to flow in but aren’t so big that the tiny mealworms will escape.

Put a few inches of a substrate like whole oats or bran or a mixture of cereals in the container. The mealworms will dig into that substrate to lay their eggs and they will eat it too. Mealworms eat grains like oats. Slice a potato or an apple in half in put half in the container. The mealworms will eat the potato or apple and get water from it too. There’s no need to put a separate water source in the container. Make sure that you change the food often and don’t let it get moldy.

You will need to buy a couple of dozen mealworms from a pet store to start off your mealworm container. Put the mealworms in the container and put the container somewhere warm. The idea temperature for mealworms is around 72 degrees. If you put them someplace cold the cold will stop all development and put the mealworms into suspended animation. If you have ever wondered why mealworms that you buy are kept refrigerated that’s why. The cold makes them go dormant.

Let the mealworms continue developing and after a couple of weeks they will go through the growth process to become darkling beetles. The beetles will mate, the females will lay eggs, and your container will be stuffed with mealworms before you know it. Just keep feeding the mealworms and you should have a steady supply of them that you can use to feed your chickens, birds, lizards, and other animals.


Pets like

leopard geckos

will feast on mealworms.


A Complete List Of Foods Mealworms Eat

You can feed mealworms almost anything that you have in your kitchen including:

  • Oats or oatmeal
  • Bran
  • Apples
  • Bananas
  • Kale
  • Berries
  • Seeds
  • Oranges
  • Coffee Grounds
  • Grapes
  • Lettuce of all kinds
  • Watermelon
  • Potatoes
  • Barley
  • Cereal
  • Rice
  • Peaches
  • Pears
  • Mango
  • Cat food
  • Dog food

And many others. Mealworms get most of their hydration from fruit so if you’re raising mealworms make sure that you’re putting some fruit in their habitat as well as other foods.

What Don’t Mealworms Eat?

There are not too many things that mealworms won’t eat except fruits belonging to the citrus family and onions. They’re easy to keep and raise so that you will have a steady protein rich food source for your chickens, lizards, birds, and other pets.

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About the Author

Lex is a green-living, tree-hugging, animal-lover, who at one time was the mother to twenty one felines and one doggo. Now she helps pet owners around the globe be the best caretakers for their most trusting companions by sharing her experience and spreading love.

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