Words to know before you read


  • Chrysalis- Third stage of butterfly life cycle. Same as pupa.
  • Emerge- To come out of something.
  • Molting- Shedding of the skin, so that the larva can grow.
  • Puddling- When butterflies crawl all over the ground near shallow water.
  • Pupa- Third stage of life cycle, when larva changes into an adult. Also called a chrysalis.

To learn more about the life cycle of a monarch butterfly,
place your mouse cursor on any part and click.


eggs A monarch begins life as a single, greenish egg attached to the underside of a milkweed leaf. The worm-like larva grows inside the egg. When it is ready, the larva chews a small hole in the egg shell and wriggles its way into the world. After a few minutes, the newly hatched larva has its first meal -- the remains of its egg. Female monarchs lay one to three eggs on the underside of milkweed leaves. This process is repeated until the female has laid hundreds of eggs.
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monarch larva
After eating the shell, the larva begins to eat milkweed leaves. Milkweed is the only plant that monarch larvae will eat. The larva eats and grows, grows and eats. The larva grows so much that it outgrows its skin, much like outgrowing old clothes.

In order for the larva to keep growing, molting must occur. The old skin splits, revealing the new skin underneath. The larva wriggles free of the too-tight skin. After freeing itself, the molted larva often eats its old skin before moving on to more milkweed leaves.
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J-position

After shedding their skins, monarch larvae continue to grow and will have to molt four more times. The last molt is much different than the others. The larva crawls away from its milkweed plant, searching for a suitable place. Some larvae will travel longer distances than others. When the larva has found a suitable place, it weaves a silk mat with a "button" in the center. Once the mat and button are ready, the larva grabs the silk with its legs and hangs upside down. The front part of its body will curve to make a "J-shape."
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early chrysalis
Once in the "J", the larva molts for the last time. The skin splits behind the head, and the larva wiggles while it hangs upside down to remove the old skin. This final molt is the trickiest, because the larva must shed its old skin and still hang onto the silk button. Once the larva embeds a hook-like structure at its rear end into the button, the rest of the skin can slip off.
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chrysalis
When the skin fall off, the larva becomes a pupa. The monarch has no eyes and no antennae. It has no legs, and it cannot move. All of the major changes in body shape, size, and arrangement happen. In monarchs, this stage can last as long as a week. At the end of it, an adult butterfly will emerge from the chrysalis.
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butterfly emerges
A newly emerged butterfly will wait two or more hours before it can fly. New wings are small and shriveled, so the butterfly pumps body fluid through its wing veins in order to make them get bigger. Then, the monarch has to wait for air to replace some of the fluid. Until this happens, the monarch cannot fly, and its wings are easily damaged.
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adult monarch
After the wings have hardened, the butterfly flies away to find its first meal. From this point on, the monarch drinks all of its food. The butterfly will visit several different kinds of flowers to get its nectar dinner.
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Not only do adult monarchs need to drink nectar, but they also need to drink water. You can see them puddling in and around damp ground.

Adult monarchs begin mating in the spring, before they return to their summer range. Female monarchs will generally lay one to as many as three eggs on the underside of milkweed leaves. She does this many times until she has laid hundreds of eggs. These eggs will hatch into larva, pupate, and become adults in the summer. These new adults will also mate. The new females will lay eggs as they fly northward. This cycle repeats throughout the summer.

Finally, in September, mating stops. The last generation of the summer is the one that will migrate to the overwintering grounds.




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