Metamorphosis

Look:

EGG --> LARVA --> PUPA --> ADULT

The four stages mentioned above and portrayed in the drawing to the right refer to the stages of complete metamorphosis. The drawing shows the four stages of the Monarch Butterfly. The striped caterpillar is the larva, and the roundish thing at the top right is the pupa. The picture on the right in the next paragraph shows a backyard caterpillar whose identity I do not know, but it sure is a nice one...

Many insects, especially primitive ones, undergo simple metamorphosis, in which the egg hatches into a special kind of larva called a nymph. This nymph looks at least vaguely like the adult, only smaller and with less developed wings, and matures into a larger adult, skipping the pupal stage. Dragonflies, mayflies, and stoneflies undergo simple metamorphosis.

During complete metamorphosis, larvae are often worm-like; caterpillars such as the one in the colorful picture are insect larvae.

The pupal stage, which is usually an inactive "resting stage," varies dramatically from insect group to insect group. Some pupae develop inside cocoons, as in the case of bagworms. The pupae of many butterflies develop into beautiful chrysalises (singular chrysalis).

Since most of us learn about insect metamorphosis as early as primary school, it's easy to accept the phenomenon as just the way things are, as something ordinary and to be expected. However, we need to step back and look at this process with fresh eyes. Just imagine: Here we're dealing with the most prolific, in many ways most successful, form of life on earth, and these animals don't grow up the way we do!

Most insects spend most of their lives in a humble, wormy form, doing little more than eating like crazy. Then one day they simply stop eating, go into some kind of daze, and enter their pupal stage, which looks inactive from the outside but which inside is an absolute hurricane of change. Then finally one day this dead-looking thing splits like a ruptured watermelon, and out pops a creature profoundly obsessed with sex!

With insect metamorphosis, maybe nature is teaching that revolution can be part of evolution, and that expressing oneself with flair can be acceptable.