The Metamorphosis of Butterflies

There are few insects that fascinate us like butterflies. In their filigree moth or butterfly stage, they are often breathtakingly beautiful. As caterpillars, they can be cute, but also cause devastation if in huge numbers. Humans, too, have a secret desire to metamorphose…

But first, the facts. According to the student edition of Encyclopedia Britannica, metamorphosis is “a series of dramatic changes in an organism’s body shape and structure as it develops after hatching or being born.” The transformation of a caterpillar into a butterfly is just one example of a metamorphosis that occurs in thousands of insect species and amphibians.

As this diagram of the butterfly lifecycle shows, the complete metamorphosis of butterflies and moths involves four stages: 1. the egg, 2. the larva (caterpillar), 3. the pupa (also called chrysalis or cocoon) and 4. the adult.

Image: ouf-ouf

A very neat butterfly or moth in Chaddlewood, Plymouth, worked on this eggsellent piece of art:

Each moth or butterfly female lays around 100 eggs, of which 80% will hatch, and this takes about three days. We’ve all seen tiny, whitish butterfly or moth eggs at the underside of leaves.


Don’t get close to me! A poisonous, stinging Saddleback caterpillar.

The next stage as a caterpillar involves rapid growth and therefore eating everything in the caterpillar’s sight. Caterpillars have an exoskeleton, that is a skeleton on the outside, which they shed whenever it becomes too small, approximately five times during their caterpillar stage.

This Saddleback caterpillar sure looks unusual in appearance and colouring but even humans should refrain from touching this critter as the hollow hairs or spins are connected to poisonous glands below. Upon contact, one experiences a burning sensation similar to a bee sting. The affected skin will show an inflammation and irritation that can last a day or two. So hands off!


A caterpillar in full pupation mode.

At the chrysalis stage, the caterpillar has pupated (yes, there is a word like that) and created a cocoon where the transformation to butterfly or moth takes place.

A web of thousands of Eastern Tent caterpillars that took over Wyndham in upstate New York recently.

If in droves, the chrysalis stage can be a fairly creepy one for humans as caterpillars can form whole webs before or during pupation that literally cover everything.


Image: Yzzordorex Sayar’u


Close-up of a Western Tent caterpillar web (malacosoma californicumcaterpillar).

Says Flickr user Yzzordorex Sayar’u about an experience she had in Colorado:

“The caterpillars were bad, but the moths – much worse. The glow cast by streetlamps at night was clogged with moths to the point that it looked as though it were snowing.”

Hmm, sounds creepy to say the least, but it is over soon as moths or butterflies only take four days to change from pupa to adult. And then, it’s time for the big moment…

The true metamorphosis! A butterfly emerging from its cocoon.

The butterfly’s white abdomen is still inside the shell. In the upper right corner, we can see various silk strands from the caterpillar stage. The butterfly still has to unfold its colourful wings and they have to harden.


Sometimes, after pupation, the result is as stunning as this Golden Birdwing (troides aeacus thomsoni) at the Butterfly Park in Bangkok, Thailand.

Here’s a picture from a butterfly nursery (yes, there’s a place like that) that depicts the last two stages from pupa to butterfly.


This little boy surely wants to be a beautiful butterfly.

But what about us, the humans? Aren’t we more than a bit crazy about butterflies? Think about popular expressions, like having butterflies in one’s stomach. Or look around your house: can you see any butterfly-inspired designs?

What’s your favorite butterfly or moth? If you’re not sure, find some inspiration in our article about amazing moths with multiple personalities. Or, if you like to be freaked out, read about the evil caterpillar invasion of Liberia not too long ago…

Source: 1, 2