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Pillars, pillars everywhere!

Cecropia caterpillars

What did I do over my summer vacation? (I didn’t catch COVID-19, so that was good!) I raised caterpillars. And more than a few of them!


My two female cecropia moths laid their eggs in the latter days of June, and the first eggs hatched on July 6! The adult moths only live long enough to lay their eggs, so mom and dad are long gone when junior arrives!

The caterpillar’s life is broken into periods known as instars. It hatches into instar one and it eventually spins its cocoon at the end of instar five. Each instar is about one week, with the exception of instar five, which is two weeks long.

The caterpillars can only grow so much in their skin, so they molt from instar to instar. And the cecropia caterpillars have some amazing color changes in the early instars!

Cecropia caterpillar instar 4

The caterpillars are about 3 mm when they’re born, and they’re black. After about a week, they molt into instar two, with bright yellow skins and black hairs. A week after that comes instar three, with green skins and multi-colored tubercles (the colored bumps on their backs and sides that contain spikes—they aren’t poisonous, but if you get whacked with a spike you feel it!) Instars four and five have bluish-green skins and more pronounced tubercles. By the time they’re ready to spin their cocoons the caterpillars are 4-5″ long! 

My two cats watching the pillars

My cats were fascinated by the caterpillars. They didn’t flit around like the moths, so Gus and Baloo didn’t see them as a food target, but the buggies were constantly crawling and eating leaves so they were fun to watch.

The caterpillars lived in a terrarium I have in my office. But they were getting big by the time they hit instar five, so I gave them all a break and moved 40 of them outside into a screen cage. The day I moved them, I had two eager assistants!

And they continued to grow! This one guy must have been crawling around near the doors of my terrarium (which I left open when I was in the room—air flow)…because I glanced over and he was crawling across the table!

So how many caterpillars was I caring for? With two females laying, I knew I was going to have a ton of eggs…and I wasn’t sure how I’d be able to raise that many ‘pillars. As the eggs were laid, I sold off about 275 eggs. And that left me with somewhere between 375 and 400 eggs. (Each female lays between 350-400 eggs!) And they all hatched!

This video was taken on August 14, and you can see the first few cocoons built. These guys are big! And what you hear is their munching, which goes on non-stop for 24 hours a day!

Yesterday the last caterpillar spun his cocoon, which brought a welcome silence to my office!

Swarming caterpillars in the absence of food

I’m not freaked out by the caterpillars…except when they’re big and they’re crawling over each other! This is the single best motivator to go out and cut them more branches.

The best take-home memory of the summer was in late August when I was out early cutting (I was cutting 40-50 2-foot branches each day!) A jogger ran past and he thanked me for clearing the sidewalk. He said, more people should be aware of runners’ needs! I looked down at my branches stuffed in my backpack and I looked back up at his rapidly disappearing figure, and I said, “Yeah, my caterpillars like it too!”

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