Monarch Life Cycle

The Monarch butterfly has a four-stage lifecycle: egg, larva (caterpillar), pupa (chrysalis), and adult.

1. Egg: The female Monarch butterfly lays her eggs on the underside of milkweed leaves. The eggs are small (about the size of a pinhead) and are a pale yellow color. They hatch into caterpillars after about 3-8 days, depending on the temperature.
2. Larva (caterpillar): When the eggs hatch, the caterpillars begin to eat the milkweed leaves. They go through several stages of growth, molting (shedding their skin) and increasing in size as they eat. After about two weeks, the caterpillar is fully grown and ready to enter the pupal stage.
3. Pupa (chrysalis): The fully grown caterpillar attaches itself to a twig or other surface and sheds its skin one last time to reveal a bright green pupa (chrysalis). Inside the chrysalis, the caterpillar’s body undergoes a transformation into a butterfly. This process takes about 10-14 days.
4. Adult: When the transformation is complete, the adult Monarch butterfly emerges from the chrysalis. It pumps fluid from its body into its wings to expand and harden them, and then it flies off to find nectar from flowers. The adult butterfly will live for about 2-6 weeks, during which time it will mate and lay eggs to begin the cycle anew.
5. Migration: Monarch butterflys undertake a migration from the United States and Canada to the mountains of central Mexico and back again each year.

The Transformation

When a Monarch butterfly larva (caterpillar) is ready to transform into a chrysalis, it will first attach itself to a twig or other surface using a silk-like substance that it produces from glands on its back. It will then shed its skin one final time to reveal a bright green pupa (chrysalis).

Inside the chrysalis, the caterpillar’s body undergoes a process called metamorphosis, during which it breaks down into a kind of soup and then reforms into the adult butterfly. This process is controlled by hormones and other substances that are produced by the caterpillar’s body.

During metamorphosis, the caterpillar’s body parts are reorganized and rearranged. Its legs and antennae are absorbed back into the body, and new wings and other adult features begin to form. The chrysalis also changes color as the transformation progresses, becoming more opaque as the butterfly inside develops.

After about 10-14 days, the transformation is complete and the adult Monarch butterfly emerges from the chrysalis. It pumps fluid from its body into its wings to expand and harden them, and then it flies off to find nectar from flowers.