What would you do for the power to fly? How about shedding your skin and dissolving your own muscles? Now, believe it or not,
that gruesome process is how caterpillars earn their wings. Here's what you might not know about what's inside a
caterpillar's "cocoon." Contrary to popular belief,
this is not a cocoon. Only certain moths build cocoons, which are like a silky sleeping
bag that covers the insect. This, on the other hand, is
what's called a chrysalis. It's not a sack or a pouch; it's actually the caterpillar's own body. When it's time for the
transformation to begin, the caterpillar's body ramps up production of a hormone called ecdysone, and that causes it to cast
off its outer coating, sort of like how a snake sheds its skin. And underneath is a hard shell similar to the exoskeleton of a beetle. After that, life for the
little caterpillar gets oozy. First, it releases
enzymes called caspases. These rip apart and dissolve
cells in its muscles, digestive system, and other organs. But the enzymes don't quite
liquefy all of the caterpillar. They leave key structures
intact, like breathing tubes. At the same time, specialized cells called imaginal discs start waking up. Before the chrysalis stage,
these discs were kept dormant by a series of hormones
in the caterpillar's body. But once the transformation begins, those hormone levels take a nosedive, giving these discs the opportunity
to do what they do best: build a butterfly. You see, each disc
contains the genetic recipe to form a different adult body part, starting from the inside out. After one week, the digestive system of the butterfly is well on its way. And by day 16, the
adult's legs, wings, eyes, and mouth are all present
and in working order. Now, two weeks is a remarkably short time for all of this to happen, since each imaginal disc starts
out with only about 50 cells and must multiply those into thousands just to form a single wing. And if you checked out the
chrysalis around day 16, you might even be able to see those brilliantly colored wings. Because for some species, their chrysalis turns transparent in their final days of metamorphosis. Now, fully formed, it's
time to hit the road. The chrysalis splits open down the center, and the butterfly escapes. Meanwhile, a reddish liquid spills out. That's all the waste the butterfly, née caterpillar, produced during its stay. Once its wings expand and
harden, it's ready to mate, pollinate, and slurp nectar
to its heart's desire. But one of the most
interesting parts of all? Research suggests that butterflies and moths can remember
their caterpillar days. In one study, researchers
trained moth caterpillars to associate an odor
with an electric shock, so whenever the larvae
smelled it, they'd move away. But even after they
transformed into adult moths, they still avoided the scary smell. It makes you wonder what else they could recall from their younger days.
