Category: Butterflies, moths & caterpillars

The black swallowtail caterpillar has changed significantly since last week.  Instead of being dark with a white patch, it now has light green and black stripes with yellow spots.

Yesterday, I noticed the caterpillar was very still and wasn’t eating.  I wondered if it was okay.  Looking closer, I found it was beginning to molt (shed its old skin).

Caterpillars have a tough skin called an exoskeleton.  The skin doesn’t expand, so the caterpillar must shed its old skin to grow bigger.  The black blob in this image is the old skin.  The caterpillar also sheds its face mask, so its face is quite pale at first.  The feet are initially white, but turn black later.

A bit later, the caterpillar ate its old skin.  This is common and it is a way for the caterpillar to reuse the nutrients in the old skin.  This seems rather yucky to me, but it’s a good example of recycling!

Here’s the caterpillar in its new skin.  14 days after it hatched it is an inch long – 4 times longer than it was a week ago.  Talk about a growth spurt!

The black swallowtail butterfly caterpillar has emerged!

When I checked the egg last Tuesday at noon, I discovered it had turned dark.  I looked again at 4:30 and saw a small black dot.  Using a hand lens (a strong magnifying glass), I discovered the caterpillar was out and eating its egg shell.  By 6:30 the egg shell was gone.

Since then the caterpillar has been eating dill and growing.  As of  day six, it is about a quarter of an inch long.  It’s black with a small white patch in the middle and spines along its back.

I created a cage using a plastic shoe box (8 x 13 inches), nylon tulle from a fabric store, and elastic ribbon.  The dill is in a florist tube filled with water.  I’ll keep the cage indoors where there is plenty of light but no direct sun, and where I can watch it.

The caterpillar is the small black spot on the dill in the image above.  I look forward to watching it grow and change.

I started raising native Kentucky butterflies four years ago.  It has been a relatively easy and enjoyable learning experience.  Black swallowtails (Papilio polyxenes), also known as parsley butterflies, are one of my favorites and one of the easiest to raise.

Last week I saw a black swallowtail butterfly fluttering around my small patch of dill, parsley and fennel plants.  I grow these plants partly to eat, and also to attract the butterflies.  I have found eggs on these plants in the past.  Sure enough, when I looked later I found this tiny light-colored egg on a small dill plant.

I have brought the plant and egg inside.  I hope to photograph the black swallowtail’s life cycle.  I look forward to watching it change into a caterpillar, then a chrysalis, and finally an adult butterfly like the female above.  I am checking the egg daily and will report the happenings.

A friend gave me a cocoon in early March.  I felt sure it contained a moth, but I didn’t know what kind.  I put the cocoon in a cage outside the dining room window where I could watch it.

Recently, I looked out to see this big, beautiful moth that had emerged – one I had never seen before.  It had a wingspan of about six inches.  Using my Field Guide to Insects and Spiders of North America by Arthur V. Evans, I discovered it was a Polyphemus moth (Antheraea polyphemus) and that its range is most of the U.S. and Canada.  The information on Wikipedia was also helpful.

The moth gets its name from these big spots on the hind wings that look like eyes.  In Greek mythology Polyphemus was a giant who had one big eye.  The moth’s eye spots are thought to confuse and scare away its enemies.

I took this image shortly after the moth emerged.  I think the cocoon now resembles a finely crafted miniature basket and I’m amazed that the caterpillar could create such a work of art.

This has been another fascinating adventure in the ways of nature.  My thanks to Dave Leonard for sharing the cocoon.