Metamorphosis – What is it for Bugs?

Did you know that all insects undergo metamorphosis during their lifetime?  Most insects are born from eggs and then change in order to become an adult.  The process of changing is called metamorphosis and can be either complete or simple.

metamorphosis, caterpillar

The larva form, caterpillar, of a Painted Lady Butterfly.

Insects are all around us in the world.  You can find them crawling on the ground, flying in the air, or even living under or on water.  In fact, there are far more insects in the world than there are other animals.  If you want to learn more, you can read about some of the common bugs of the Rocky Mountains.

However, the one thing that most insects have in common, no matter if they fly, crawl, or swim is that they change their form during their lifetime.  Additionally, there are a number of other things that make a bug a bug.

metamorphosis, butterfly

The adult form of a Painted Lady Butterfly.

What is Metamorphosis?

Most all insects (there are a couple of exceptions as there are with most things) start their life being  born from an egg.  Then as they live and grow older they change their form once or more until finally they become an adult that can reproduce.

Metamorphosis is a major change in the appearance or structure of an animal that occurs after the animal has been born.

What Are the Two Kinds of Metamorphosis?

The two kinds are complete and simple.

simple metamorphosis diagram

An example of simple metamorphosis.

Simple Metamorphosis: there are three stages in an insect’s life – egg, larva or nymph, and adult.


complete metamorphosis, diagram

An example of complete metamorphosis.

Complete Metamorphosis: there are four stages in an insect’s life – egg, larva, pupa, and adult.

The major difference between these two is that some insects have a pupa stage.  This pupa stage is a resting stage, during which it seems that the insect performs magic.  The insect disappears inside its pupa, which could be a chrysalis (for butterflies) or cocoon (for moths).  Then somehow, inside that pupa the insect completely transforms itself into a different shaped insect.  Oftentimes the adult is more complex and beautiful than the larva.  It is like a magician put a caterpillar into a hat, whispered some magic words, and then pulled out a beautiful butterfly.

One of the differences between a butterfly and moth is the pupa they make – a chrysalis or cocoon.