Imaginal Discs (or, Why You Should Never Believe Phrases Written in Calligraphy)

You know those inspirational cards and posters that say something like, “Just when the caterpillar thought the world was ending, he turned into a butterfly”?

I understand the idea—that sometimes tremendous and painful or frightening upheaval leads to wonderful things—but I think people need to stop using insect metamorphosis as the comparison.

Why, you ask? Because insect metamorphosis is horrible. And the final product not only bears very little resemblance to the initial one, but it is only in the loosest sense the same creature at all.

Here’s what happens: in the pupa, the caterpillar doesn’t just go through some dramatic changes akin to the special effects we see in werewolf movies, where, as it grimaces, its legs lengthen and its wings sprout from its back. No, the caterpillar dissolves. Literally.

All that’s left of it, apart from a liquid mess, are these clusters of cells called “imaginal discs” that contain all the genetic information and coding necessary to create a butterfly.

The cells in these discs divide and develop into body parts by sucking up energy from the swampy (but proteineous) remains of what was once the caterpillar—and it is the product of the development of those discs that is the emerging butterfly.

Not exactly inspirational, is it? More like a horror movie, right? I mean, here’s this caterpillar, going about its business, living its life, and all the time inside it are these little clusters of cells just waiting for the time-bomb of the caterpillar’s developmental cycle to make it disintegrate into a sack of ooze so they can become a beautiful flying creature.

Imagine being seeded with the germs of your own destruction—or ascendance, depending on how much importance you place on the fact that the butterfly shares its genetic material with the caterpillar. Imagine being just the vehicle—and food truck—for the real, reproductive, snazzily winged main event.

Maybe it is a transcendent sort of a concept. But, I don’t know; it just doesn’t say “greeting card” to me.

{A note: I do write all text and take all pictures. Please do not reproduce either without my permission.}