Have you ever wondered exactly how a caterpillar changes into a butterfly? We've been pondering this question, particularly since when we leave at night they are still caterpillars and when we return in the morning they are chrysalises. What happens overnight?
Well the answer is both incredible and disgusting. Essentially the caterpillar melts in the beginning stage of metamorphosis. To get to the pupae stage a caterpillar has to digest itself, turning into what Scientific America terms "caterpillar soup" inside the chrysalis. The genetic makeup for the butterfly has been hiding inside the caterpillar all along, and now it comes out. These are called imaginal discs, and they feed off the rest of the caterpillar mush to grow into it's final butterfly form.
So what comes out as a butterfly has a completely different genetic makeup than it's caterpillar origins. Want to see if happen? Here's a great time-lapse video from Youtube:
It's an amazing snippet of the monarch caterpillar lifecycle to witness, but honestly it's still gross.