While weeding the onions I discovered this tiny chrysalis. The neighborhood butterfly expert says it’s a Baltimore Checkerspot – a butterfly that has mostly black wings (with some white spots) that are rimmed with orange. I’d seen them flying around, and even caught sight of one of the bristly caterpillars hanging out on plantain – a weed I was pulling from the onion beds.
I want to watch the butterfly emerge, so I taped the onion leaf to a protected area on my porch. Every day I run out to check it, to see if “my checkerspot” has got its wings.
A chrysalis is the “pupa” of the butterfly. The caterpillar (larvae) spins a silk pad on the underside of a leaf – or in this case, an onion leaf shaded by weeds – and then hangs upside down and begins changing form.
What we see on the outside is this: the case that holds the metamorphosing butterfly within. It may look as though it’s resting, but there are a lot of changes going on inside. The caterpillar's tissues break down and completely reorganize.
Groups of cells, called “imaginal disks” give rise to things like wings. Or legs. Even antennae. The dissolving caterpillar provides a nutrient-rich fluid for these cells. They begin growing really fast, differentiating into muscles, heart, nervous system.
All this happens inside the chrysalis – so when the butterfly is finished forming and ready to emerge, there’s a lot of waste products in there too. That’s the reddish-colored liquid that sloshes out after the butterfly emerges.
If you go hunting chrysalides (that’s more than one chrysalis), make sure you check protected spots: the undersides of leaves, shady stems, even the sides of rock walls. You can make a net cage to protect chrysalides from predators, but make sure you’re around to release the adults once they emerge and have dried their wings.