Biology Is Weird — Glow-ups! You have to crawl before you fly.
A glow-up. Every teenager’s biggest wish. We all hoped that the large noses, acne and gangly limbs were just precursors to a future in which we were runway perfect. Unfortunately, that doesn’t always happen for us humans, sometimes, those imperfections follow us all the way to the grave. Sorry guys. But, you know who has a 100% guaranteed glow-up? Caterpillars.
Caterpillars know that no matter how tube-like they’re shaped or how long it takes to get anywhere with their little feet, there is a future in which they are beautiful butterflies. Or moths. But hey! A glow-up is a glow-up, even if everyone would prefer to be a butterfly. No offense, moths.
But how do caterpillars get to experience this literally life-changing event? Most butterflies live for only a few weeks, some species survive a few months so caterpillars have to be snappy if they want to enjoy their wings for a while. Depending on the lifespan of the butterfly, caterpillars generally hatch, eat and metamorphose within a few weeks.
During the few weeks they live, caterpillars eat. A lot. They grow very rapidly at this stage and so they ‘molt’. Since caterpillars have an exoskeleton, they often outgrow it because of how much they eat and so they shed it. Then eat that too. Sometimes, their new skin is a different color. Each time they molt is called an ‘instar’. Some caterpillars can molt up to 5 times before they metamorphose.
Then it’s time for the big change. Moth caterpillars will spin a silk cocoon while butterfly caterpillars molt one last time to form a chrysalis. They do this while hanging upside down in a hidden place from a leaf, stem, root or branch. This is where it gets serious. The caterpillars then release enzymes that digest their bodies and form a sort of caterpillar soup. Gross, I know.
Most caterpillars hatch with or form ‘imaginal discs’ which contain cells for body parts it will need as a butterfly or moth, these discs do not dissolve but rather ‘feed’ on the caterpillar soup. The caterpillar basically breaks itself down to a puddle of cells and builds itself up again to become the beautiful butterflies (or moths) that we adore. That sounds painful, disgusting and slightly cannibalistic. Still hoping for a glow-up?
This process generally takes about two weeks, but some species stay cocooned to avoid the winter. Weaklings. Once the butterfly is fully formed, it breaks out of its self-made prison and hangs upside down to let its wings dry and strengthen. Then it flies off to find food, love and a happily ever after.
That is it for today, and I think the important takeaway is that beauty is overrated. And just because I feel bad about insulting the moths, do me a favor and look up the Luna moth and Oleander Hawk-Moth. I hope you learned something or at least smiled once. Thank you for coming to my Ted talk.
