Search: what happens inside a cocoon
Why: The other night on "Ugly Betty," some old lady made Betty watch a butterfly come out of a cocoon.
- When the caterpillar has eaten enough, it turns into a pupa. It stops eating, finds somewhere safe, and becomes very still. Pupa never eat and seldom move at all.
- It molts its skin the same as it does when growing, but instead of another larval skin, it secretes a thicker, stronger pupal skin. Generally, the pupa then breaks out of the old larval skin, though in many moths, the pupa remains inside the old larval skin. You can often find the remains of the caterpillar skin around the tail of a Butterfly pupa.
- A lot of the caterpillar's old body dies. It is attacked by the same sort of juices the caterpillar used in its earlier life to digest its food - it sort of digests itself from the inside out in a process called histolysis. Not all the tissue is destroyed, however; some of the old tissue passes on to the next stage.
- Special formative cells called histoblasts - until now dormant in the larval body - come into action. They form a new body out of the soupy mess that the digestive juices have made of the old caterpillar body. They do this using histogenesis, which is the same biochemical process that all insects use to turn food into part of their bodies. They make a new heart, new muscles, new digestive system - everything.
- During this whole time, the butterfly or moth can't excrete anything, so all the waste products accumulate. When it emerges from the chrysalis, it leaves behind a reddish-brown meconium that is made up of all the nitrogenous waste.
The More You Know: Have you ever seen a glasswing butterfly? I just love them: