From Caterpillar to Butterfly

Could this be the first time that Echo sees a caterpillar? Imagine his fascination. The caterpillar seems almost self-assured. Confident. Echo is curious. Perhaps the tiny larva is telling the story of its life!

Echo’s new caterpillar friend is that of a painted lady butterfly. It eats and eats and eats, outgrowing and shedding its skin four times. Once fully grown, the caterpillar attaches itself to a stem and sheds one last time, becoming the chrysalis you see above.

But how is it that a caterpillar becomes a butterfly? Well, strictly speaking, it doesn’t. To understand this, consider a butterfly egg. Inside there is a single cell that divides into two. Those two cells divide and now you have four and so on, differentiating along the way until you have a caterpillar. Some of the early cell groups, however, are not part of a soon-to-hatch caterpillar, but of a butterfly. These are known as imaginal cells. They stop dividing while the other cells continue their creation of a caterpillar!

Now here’s the rub. Most of what used to be a caterpillar breaks down into this nutrient-rich ooze. And those dormant butterfly starter cells, the imaginal ones? They awaken and continue their division, using up the ooze as they go.

Some parts of a caterpillar, like the gut, do not liquefy. Instead, they are modified to become parts of the butterfly. In this way, a caterpillar is an organ donor and a source of raw materials.

For fun, put your curiosity to the test. Do this with the budding scientist(s) in your family. Wonder about how any of this actually works. What sort of things might affect the process? Ask questions. State a hypothesis. Design an experiment to test it. You get the idea. And just like Echo, stay curious!
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Photos used with permission, all rights reserved:
• Echo Meets Caterpillar © 2021 Greg Dancer, Super Science Sampler Instructor
• Painted Lady Chrysalis ID 184697936 © Mrehssani | Dreamstime.com
• Painted Lady Butterfly © 2021 John Aviste
Reference:
1. Van-Wright, D. (2015). Butterflies, A Complete Guide to Their Biology and Behavior. Comstock Publishing Associates a division of Cornell University Press.