There are more shapes to a chrysalis than I could ever imagine. I know this because I stared at several hundred chrysalides (that's the fancy plural form of chrysalis) for two hours -- waiting for one, just one, winged insect to emerge.
As part of our Black Box story, "Goo and You," I found myself looking at chrysalides down in Gainesville, at the McGuire Center for Lepidoptera & Biodiversity. They have the Rearing Lab, a room that's really more about its wall:
In this wall, a plexiglass space with 16 shelves (four columns of four shelves), hang hundreds upon hundreds of butterfly pupae gathered from all around the world, from Malaysia to Costa Rica; at any time, representatives from up to 90 tropical butterfly species hang in this hollow space, waiting to emerge from their chitin shells. And visitors, like myself, wait to see the magic happen.
Using a hot glue gun, chrysalides are attached upside down to a piece of paper, which is marked at the very least with the species name, and then hung from beneath the shelves. Behind the wall, you can see the room where the workers remove the newly emerged butterflies from the plexiglass chrysalis case, and then transport them to the nearby butterfly rainforest.
Standing in front of hundreds of mostly still* chrysalides, waiting for something I should have seen far long ago but realized I hadn't, there's nothing much to do but stare, scrutinizing each of nature's various dressing boxes. There were jellybeans, flower buds, twigs, bark, and shrimp...cones, snail shells, and sea shells...white, green, black, malachite. Here's a chrysalis, disguised as a leaf for protection:
The darker the chrysalis, the closer the butterfly is to emerging. So in the leaves above, the light brown casings contain a butterfly about to emerge, if one hasn't popped out yet. The change in color comes from the butterfly pulling away from the outer layer of the chrysalis as it gets ready to push out. Next are the snail shells:
The white ones are empty, butterflyless...and then, here are beauties that look like tight, glistening, green pasta shells:
You'll notice two pools beneath each of the newly emerged butterflies (sadly, I missed their birth!) -- that's meconium, also called the pupal liquid. It's dead cells from the gut, left over from metamorphosis, expelled from the butterfly after emergence (for those parents out there, you'll also remember that your newborn has their own version of meconium). A reddish liquid, it's often mistaken for blood, but isn't.
And then, finally, we get to my favorite chrysalis, the gold:
These chrysalides look like they are jewelry; not even butterflies, but ants, pounded out of metal foil. But they aren't.
Made out of the same chitin as other chrysalides, scientists suspect that somehow, the cells are layered in such a way that they reflect light, appearing metallic. Here's a butterfly whose pupa is merely decorated in gold dots, nature's accessories:
In fact, this gold coloring is so common in butterfly pupa, that is how it earned its name: chrysalis comes from the Greek word for gold, chrysós.
As for what purpose such all-over metallic coloring or dots perform? Science isn't really sure. Perhaps camouflage -- maybe the gold looks like dew drops; perhaps a light filter, preventing harmful wavelengths from penetrating the shell. Recently, a scientist using a micro-scanning technology saw that in monarchs, what is called the "gold crown" -- a circle of dots around the abdomen of the chrysalis -- are in fact openings that air passes through.
There's one other thing I didn't know about chrysalides, and you can see it here, if you follow the arrow:
That little tuft. You see it? Hanging off the dried pistachio-looking chrysalis in the corner? It's the shriveled-up skin of a caterpillar. See, it turns out, caterpillars don't crawl into the chrysalis...they molt into it. We all know about molting, right? As a caterpillar gets bigger and bigger, occasionally it sheds its outer layer of skin, and there's a new layer of caterpillar skin underneath that it grows into. Well, it turns out, caterpillars actually also grow the chrysalis beneath their wormy skin, so that one time, when they are big enough, they molt not into a bigger caterpillar, but into a chrysalis. The chrysalis that comes out from under the skin is soft and wet, but hardens over a few hours. So they don't crawl into the chrysalis, they morph into it, shaking off their old caterpillar skin. But, sometimes, that skin stays attached to the pupa by the skinniest of threads; it just hangs out, so you can see some semblance of the earlier creature that led to the chrysalis.
So. I know you're wondering: after two hours of waiting, almost missing my flight, did I see anything bust through these decorative homes? With ten minutes to spare...I can say that I did. I'd like to introduce you to our butterfly, popped from a chrysalis that appears like a decomposing stick; a piece of detritus. We like to call her Radiolab (she's the furthest one to the left, with that bit of light reflecting):
*Believe it or not, it's not uncommon for a chrysalis to wiggle. Here's one that blew me away with its aerobics: