Caterpillars bring butterflies, like the black swallowtail

We keep finding caterpillars in our garden.

I wrote about a silkworm caterpillar we raised indoors until a winged Io moth emerged in July. In August, my wife, Kathy, found another caterpillar — aka larva — feeding on parsley, the host or food plant for a black swallowtail larva.

We brought the larva indoors and placed it with parts of the parsley plant in a large, clear, ventilated container to keep our house cat from having the worm for lunch.

The larva grew bigger and bigger, feeding on parsley leaves we continually supplied.

Eventually, the larva encased itself in a hardened shell called a chrysalis looking like a worm-style sarcophagus. What happened next was a metamorphosis that transformed the larva into a pretty butterfly.

The transformation within the chrysalis was grisly. Enzymes kicked in to dissolve the larva’s body into a gooey soup. Simply put, the caterpillar digested its own body.

But let’s go back to when the caterpillar was developing as a tiny worm inside a tiny egg. Certain cells were being organized into groups called imaginal discs that would form a sort of template for the butterfly’s body parts.

Unlike other larval tissue digested into a soupy mixture, imaginal discs remained intact. The discs drew sustenance from protein in the gooey soup while undergoing cell division to produce butterfly wings, eyes, legs, antenna and reproductive parts.

Eventually, a fully formed black swallowtail broke out of the chrysalis in a process called eclosion. It hung upside down and began a lengthy, complex process of expanding and drying its wings.

The entire process of larva to chrysalis to butterfly happened in our living room, as beheld by a bewildered cat.

The butterfly was a female as told by its black wings edged in small, cream-colored dots. A male’s wings would have been edged by a wide yellow band alongside a narrow one.

Swallowtail butterflies get their name from twin protrusions that look like tails on the hind wings. Expect to see plenty of black, giant, tiger, spicebush and pipevine swallowtails along with other butterflies, like Gulf fritillaries and red admirals, in September and October.

Autumn brings a population boom of butterflies because of multiple broods produced in the summer. Colorful butterflies flitting through our neighborhoods compensate us for the lack of abundant fall foliage.

And coming up is the huge migration of monarch butterflies — but I’ll talk about that in October.

Kathy Adams Clark / Contributor Female black swallowtail butterflies lay their eggs on parsley, dill, and carrot tops. Watch for them this fall in the garden.

Kathy Adams Clark / Contributor Butterflies, like this giant swallowtail, are plentiful in late summer and into autumn.