Monarch Caterpillar: Facts and Description

The Monarch caterpillar is a striped larva with yellow, white, and black bands on its body. It takes 1 to 2 weeks before this caterpillar molts and transitions into the pupa (chrysalis) stage.

Monarch Butterfly Life cycle Overview and Timeline

Monarch butterfly
Monarch butterfly

The Milkweed butterfly, also known as the Monarch butterfly or just the Monarch, is a member of the Nymphalidae family and belongs to the subfamily Danainae. The adult Monarch butterflies have two pairs of brightly colored orange wings with white spots and black veins along the costal areas.

Its average lifespan is 5 weeks, which is broken down into the following stages:

Egg stage1 week
Larval stage1 to 2 weeks
Pupal stage1 to 3 weeks
Adult stage1 to 2 weeks

Monarch Caterpillar Description

Monarch butterfly caterpillar last instar
Monarch butterfly caterpillar last instar

The Monarch caterpillar (Danaus plexippus) is quite simple to recognize because of its distinctively striped appearance and black, white, and yellow colors. Once it hatches, the caterpillar is almost white. As it goes through instars, its bright stripes become more yellowish, and dark ones get thicker. These caterpillars can grow up to 1 to 2 inches long.

A Monarch caterpillar will go through 5 cycles from the moment it hatches from its egg until it forms its Monarch chrysalis and emerges as a butterfly.

Free Butterfly Garden Mastery Course

Sign up for our five-email course that will teach you how to identify, observe and attract butterflies to your garden.

The caterpillar needs to shed its exoskeleton to move more freely because this outer layer will eventually get too tight as it grows.

How Poisonous Are Monarch Caterpillars?

Monarch butterflies are poisonous and bitter. This is because they absorb chemicals called glycosides (cardenolides) from milkweed leaves during the larva stage.

These caterpillars can cause the following symptoms when ingested:

  • Lack of appetite
  • Dehydration
  • Upset stomach
  • Diarrhea 

What Do Monarch Caterpillars Eat?

These are some of the host plants that Monarch caterpillars prefer:

  • Milkweed plant (Asclepias)
  • Zinnia (Zinnia)
  • Blue porterweed (Stachytarpheta jamaicensis)
  • Miss Molly bushes (Buddleja)
  • Siberian wallflowers (Erysimum)

Monarch Mimics and Look-Alikes

With their orange and black wing coloring, the Queen, Viceroy, and Monarch appear almost identical. The Queen butterflies use what’s called mimicry. It’s a survival tactic where two species have similarities in appearance or signaling. In simple terms, non-toxic Queens imitate toxic Viceroys and Monarchs and keep their predators away.

How Long Does It Take a Monarch Caterpillar to Become a Butterfly?

It takes about 2 to 4 weeks before the caterpillar fully transitions into an adult butterfly. It might take a bit longer if the larva hatches during the colder seasons.

Where to Find Monarch Caterpillar?

The Monarch butterfly is native to North America, and will migrate to Southern California and Mexico and back north. Its ideal habitats include:

  • Empty lots
  • Roadside vegetation
  • Wet meadows
  • Gardens
  • Marshes
  • Pastures
  • Open spaces

This butterfly lives in the same environment where milkweed is. You can usually find the caterpillars on the undersides of the host plants, but the eggs may also be attached to the flower buds or stems.

If you want to purchase these caterpillars, check with your local stores. You may also have the option to order them online, but they can only be shipped when the temperature allows. The larvae are usually available from the early parts of June to September.

What Do I Do if I Find a Monarch Caterpillar?

If you stumble upon a Monarch caterpillar, you don’t have to do anything special. They are usually hardy and can cope well with their environment. If you want to care for them, consider growing more milkweeds in your yard to attract them. This will also give them enough food to develop into butterflies after a few weeks.

The Best Plants for Monarch Caterpillars

Milkweeds are the best host plants for Monarch caterpillars. Other great host plants that attract Monarchs and help the Monarch butterfly caterpillar are:

  • Chives
  • Siberian wallflower
  • May night salvia

How useful was this post?

Click on a star to rate it!

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?

Leave a Comment