Changing life for bugs

PUBLISHED : Monday, 24 August, 1998, 12:00am
UPDATED : Monday, 24 August, 1998, 12:00am

Most insects alter their shape several times in their lives.

This change of form or structure is called metamorphosis and consists of four stages: egg, larva, pupa and adult.

The Common Crow butterfly lays eggs in batches of 15 on the underside of the leaves of the Blood flower. Each has an egg-cell with a yolk inside and a shell outside.

As soon as the larva hatches about five days later, it starts eating, which is its only job.

For a few weeks it eats and eats until it's full, then it spins a silk cocoon.

The pupa (or chrysalis) is a motionless development stage which allows the organism to re-organise its body tissue.

It usually hangs head down from a leaf.

About one week later, when the adult tissue has completely developed, the pupal skin splits and the butterfly struggles out.

The adult insect's job is dispersal and reproduction, so off she goes to mate, lay eggs and start the whole process all over again.

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