Nature Notes: Mystery Solved

Caractacus the mystery caterpillar has revealed his true identity at last. As a caterpillar, he puzzled us by varying the usual coloration of a monarch:

But in every other respect he acted like a monarch. He ate milkweed, grew, spun a silk button, hung in a J, and formed a green chrysalis that gradually became more transparent until this morning it looked like this.

This afternoon, we observed him emerging from the chrysalis. It was exciting for me! — I’ve never been able to see a butterfly in that moment before. The rim of the bottle hides some of the action, but I took a video that captures the basics (as well as the excited whispers of my entire family):

(I hope to improve on this… I should have some more opportunities to film emerging butterflies in our aquarium.)

After a few hours of drying and hardening his wings, and a few experimental wing fans…

we put him outside and wished him well. He’s a male monarch, as the two black swellings/spots on the wing veins reveals.

Best wishes on your journey south, Caractacus!

In other news, Goliath, our smallest caterpillar, formed his chrysalis today. He was only 4 mm long when we brought him home.

But since 8/30 he grew to just over an inch and a half. We put another caterpillar roughly his size in the jar with him, and the two became buds. They ate milkweed together. They dozed together. They spun their silk buttons together…

Then hung out together:

Then went into their chrysalises together.

My daughter is convinced that they’re a male and a female, in love.

That ends the era of replenishing our milkweed stock every day (which I am very glad about); these were the last two caterpillars to go into the pupa stage. Now we sit back and wait. Two butterflies — thirteen more to go.


Last but not least, we went back to the flooded park where we found all the caterpillars, and it had dried up some. We saw hardly any caterpillars, but there were a few. And we saw a couple of butterflies looking fresh against the muddy water. A few is better than none.

Chrysalis Formation

I took some video of a monarch caterpillar’s chrysalis forming today. The caterpillar had spun its silk button and attached itself to the underside of a milkweed leaf — not the ideal spot, as the leaf will dry out, or another caterpillar may decide to eat it. After the chrysalis was finished we removed the leaf and positioned it in a safer, more stable spot.

This video is of the first five minutes or so, as the caterpillar’s old skin is pushed off. It takes another 45 minutes or longer for the chrysalis to be completely finished, but it’s in these first eventful five minutes that the process is visible. It’s fascinating to watch, though not at all comfortable for the caterpillar, from the looks of it; transformation is definitely not a passive thing. I’m always amazed at the strength of the silk button, too, which looks so gossamer but withstands so much twisting and turning.

Often when something grand is going on, there’s an indifferent bystander, and in this case it’s another caterpillar, munching relentlessly in the left foreground…