Chrysalis Stage of Metamorphosis

Can anyone describe in scientific detail precisely how a caterpillar, in the chrysalis stage of metamorphosis, changes into a butterfly? I’ve searched the web and as yet have only found vague phrasings such as “hormonal changes”. Do we know exactly how this change takes place? Someone told me the caterpillar breaks down into a sort of juice and then reconfigures itself. That sounds dubious to me. Does it just grow new parts while constantly shedding old skin layers?



That’s basically what happens with butterflies and other insects that goes through the ‘complete metamorphosis’. The whole process is controlled by a hormone - ecdysone. The caterpillar will first form a shell around itself, then start to break down it’s own tissue with massive programed cell death. Afterwards it grows its adult tissue from ‘imaginal discs’, which are basically stem cells. It’s kind of like going through embryogenesis all over again.

Here’s a fairly detailed explanation of fruit fly metamorphosis, which as far as I know is the most well studied. Butterflies should be fairly similar.

GREAT question.