Metamorphosis

Lesson Plan - Get It!

Audio:

When we dress up in a costume, we can become anything we want.

We can be completely transformed — for a short time — into another person, a new identity, a different species, or even something unworldly! There are so many different types of costumes we can put on, and characters we can become. Unfortunately, we can't stay in costumes forever. That's not true for some insects, however; they go through a process called metamorphosis, which is very similar to playing dressup with costumes, except that the change is permanent!

Consider what you look like in your baby photos. You are much smaller, probably have less hair, and your arms and legs are shorter. As you grow, the size and shape of your body may change, but you have the same body shape and parts. We only have one body shape, while insects have multiple body plans. During complete metamorphosis, an insect's body can completely change.

Complete metamorphosis means that the insect has four stages of life: egg, larva, pupa, and adult.

The egg stage is the first stage of life, where the young insect is developing inside a protective shell.

Once the young insect is ready to leave the shell, it starts to hatch. The larva is what comes out of the egg. During this stage, insects eat a lot! They grow in size, even shedding their skin multiple times during development. When an insect sheds its skin, it is called molting.

Once a larva is finished growing, it builds a pupa. A pupa is a protective structure that shields the insect as it transitions from a larva to an adult. You can't see the changes occurring inside, but the insect is developing muscles, organs, and body parts needed in adulthood.

Finally, the adult insect is ready to emerge from the pupa. This is when butterflies appear, ready to repeat the life cycle of an insect. During the adult stage, reproduction occurs, leading to more eggs ready to start the process over!

Many insects experience complete metamorphosis, including bees, butterflies, beetles, and many types of flies. Other insects — like dragonflies, cockroaches, and grasshoppers — use another process, called incomplete metamorphosis, which only has three stages.

Incomplete metamorphosis starts with the egg, where the young insect develops. Once the insect is ready, it becomes a nymph. Nymphs spend most of their time eating, so that they can grow! They look similar to adult insects, but are smaller in size. Nymphs carry out the molting process — shedding old skin — so they are able to grow larger.

Nymphs develop into adult insects, ready to reproduce!

• Can you think of other animals that look different during life stages?
• Why do you think insects use metamorphosis?

Talk to a parent or teacher about your thoughts. All insects start from an egg, where the young organism develops into a nymph or a larva. They eat and grow until transforming into the adult insect we can easily identify!

In the Got It? section, you will learn more about molting by watching an interesting video.