Complete Metamorphosis in Butterfly

The butterfly lays its eggs on the underside of leaves, which will become food for the larva. This also protects the eggs from direct sunlight as well as from the view of potential predators. The eggs are usually tiny, round and pale yellow or green in colour.

Life Cycle of a Butterfly:

Larva:

The egg hatches after a few days to form the larva known as a caterpillar, a worm-like organism with a cylindrical body made up of a head, thorax and abdomen.

The caterpillar has a pair of powerful mandibles which it uses to chew and grind leaves.

The thorax consists of three segments each of which bears a pair of true legs with claws at the end. These legs aid in crawling and attachment to leaves.

The abdomen has ten segments. The third to the sixth segment each bears a pair of prolegs. The last segment bears a pair of claspers which ends in a double row of tiny hooks. The claspers help the caterpillar to grip firmly on leaves.

As the caterpillar grows rapidly it moults about three to four times to accommodate the increased body size.

Pupa:

The caterpillar spins a silk pad on a twig and attaches its claspers firmly to the silk pad. As it attains its full-grown size, it is suspended from the twig with its head down.

The caterpillar moults for one last time before forming a hard shell known as the pupa or chrysalis which is usually green or brown in colour to provide camouflage. During this stage, all the internal organs will develop to maturity. The caterpillar is said to be pupating or changing. 

Adult:

After a few weeks, the adult butterfly emerges from the pupa with its structures and organs fully developed. The chrysalis splits and the butterfly crawls out of the pupa.

It expands its wings by pumping fluid into the veins which harden to provide support for the wings to unfold and dry before it flies away to find food and to mate.