How to Keep a Milkweed Caterpillar

If you're lucky enough to have milkweed growing in your neighborhood, you may get to watch it become a thriving habitat for fuzzy caterpillars during the spring and summer months. These are milkweed tussock moths, commonly known as milkweed caterpillars in their larval stage. Many families enjoy raising milkweed caterpillars as pets, either for a school project or personal enjoyment, then releasing them back into the wild when they metamorphose into adults. With the right materials, caring for milkweed caterpillars is fun and easy.

Things You'll Need

  • Local milkweed caterpillars
  • Terrarium with small air holes or large, lidded jar
  • Small electric drill
  • Sharp scissors
  • Paper towels
  • Milkweed
  • Sticks
  • Spray bottle
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Instructions

    • 1

      Build your caterpillar terrarium. Most pet stores sell plastic terrariums, or you can make your own using a large, clean, lidded jar. It should be at least one gallon, although bigger is better for multiple caterpillars. You'll also need to drill small holes in the top so the caterpillars can breathe but not escape. Line the bottom of the terrarium with paper towels, then lean several sturdy sticks up against the sides of your terrarium to provide the caterpillars with extra footing.

    • 2

      Collect your caterpillars from a local milkweed plant. Using your scissors, remove the leaf or stem that the caterpillar is standing on and gently place the whole thing into your terrarium. Do not remove the caterpillars using your fingers, as they are extremely delicate and this could hurt them. Take no more than five. It's easiest to care for a small number of caterpillars in captivity. This also leaves wild caterpillars for other people to enjoy.

    • 3

      Keep your terrarium well stocked with fresh milkweed leaves. Caterpillars will not eat old or dry leaves, and it is crucial for them to have a steady supply of nutritious food. It is best to slowly mix new leaves in with older ones. Do not try to feed your caterpillars anything except milkweed leaves; they will not eat anything else. Also, make sure the leaves are free of insects, spiders and pesticides. You don't want the leaves to contain anything that might harm your caterpillars.

    • 4

      Clean your terrarium every day by removing the caterpillar waste, dead leaves and soiled paper towels. Make sure you do not accidentally remove any caterpillars while you're cleaning. Line the bottom of your terrarium with fresh paper towels when you're finished.

    • 5

      Watch your caterpillars carefully. If you notice them slowing down or changing color, they are probably preparing to pupate. The sticks you have provided will give them a study and safe place to form a chrysalis. Make sure these are high off the ground and evenly spaced so the fully grown moths have room to stretch their wings. If they cannot do this when they first emerge, they will not survive.

    • 6

      Care for your chrysalises by periodically misting the terrarium with water from your spray bottle. Soon, you will be able to watch fully grown moths emerge from them. Once they have finished emerging, it's time to let them go. In the wild, they will mate and ensure a steady population of caterpillars for next year. Be sure to release them in a secluded area so they are not eaten by birds.