Monarch Caterpillars

The tiger striped Monarch caterpillars are among the most beautiful of the caterpillars. Monarch caterpillars are usually born on and eat milkweed plants. This is helpful to the caterpillar and butterfly because the toxins from these plants are passed into the insect, which makes them distasteful to predators like birds. Even if an ignorant bird tries to eat a Monarch caterpillar, its bad taste will discourage the bird from eating any others.

The caterpillar is but the second stage in the life cycle of the Monarch butterfly. It starts out as an egg laid on the milkweed plant. The female butterfly will glue the eggs to the leaf of the plant with her own bodily secretions to make sure they're secure, then she'll leave and give no more care to the eggs or the larvae.

When it's time for the caterpillar to emerge, it will chew a circular lid in the eggshell, then pull its body free of the egg. Then, it will eat the eggshell, which gives it some nutrients before it starts to eat the milkweed.

Like all caterpillars, the Monarch caterpillar's task is simply to eat and eat till it reaches the size when it will be ready to pupate. This is about two inches long and takes about two weeks. After the caterpillar has reached this size and survived predators and other hazards, it will find a location (usually away from the milkweed) and spin a pad there. It'll attach its rear to the pad with hooks and hang in the shape of a "J" for about twenty four hours.

Then, the caterpillar's skin splits down the back and the pupa emerges. It wriggles free from the skin which is finally cast off. The pupa then hardens, and waits.

Even the pupae of Monarch caterpillars are attractive. They're mostly jade green and have beautiful dots of what look like gold along the tops and on the side.

During the pupal stage, the body of what was the caterpillar is broken down into something like a soup and slowly formed into the adult butterfly. This drastic process is known as complete metamorphosis.

Finally, the pupa case splits and the Monarch butterfly struggles out. After it emerges the butterfly rests for a while. Its wings are crumpled and damp and can't work right away. The butterfly spends a couple of hours pumping fluid into the wing veins so the wings can expand and harden properly. The Monarch butterfly then flies away to begin the process all over again. The time between egg and adult is about a month.