Metamorphosis: pupal stage


The last molt of a caterpillar is quite spectacular, the new skin is not another caterpillar-skin but a pupal-skin! In fact the dermal cells of a butterfly are trimorphic: caterpillar-, chrysalis- and butterfly-cells are in fact all the same cells!


Daphnis nerii

Pieris brassicae


The pupa is the metamorphic bridge between caterpillar and adult butterfly. often the chrysalis is erroneously called the resting stage of the metamorphosis. Nothing could be further from the truth: larval characteristics are dismantled chemically and embryonic cells divide. Just a few hours after pupation adult characteristics begin to form; tiny wings, mouthparts, thoracic muscles and legs.

If the development of the butterfly is completed, the butterfly forces itself out the pupa. The new butterfly soon starts pumping haemolymph into its wings to expand them. When the wings are completely expanded the hormone bursicon is responsible for hardening the wings.