Are There Good Caterpillars?

I have a distinct memory from when I was a kid of finding a huge green caterpillar in the yard. It had a spike on one end and was wandering through the grass. For some reason, it sparked a huge debate over whether it was a good caterpillar or a bad caterpillar. I think I remember it because I didn’t know what a caterpillar did to be bad.

Somehow the caterpillar was found wanting and left as a green smear in the lawn. To this day, I am not sure why it was found wanting.

Some caterpillars do get into the garden. Black Swallowtails, one of our largest butterflies, lay their eggs on carrots and dill and fennel. Their stripey caterpillars blend in as they munch on the leaves.

Every year, I hear a story about some gardener who found “worms” eating their dill or carrots that had to be destroyed and I feel bad for the poor caterpillars that were left in the garden.

Somehow, that sympathy does not transfer to the Cabbage White butterflies. These white butterflies are everywhere and love to lay eggs on plants in the cabbage family. The one, and only, time that broccoli grew in my yard, there were over 20 Cabbage White caterpillars on each head.

Cabbage Whites were introduced from Europe in the 1860s. They are now found all over the world, where they can be a major pest in gardens.

My world has recently become consumed with caterpillars. Fifty Promethea Moth caterpillars brought in by a volunteer are devouring Tulip Poplar leaves in the lobby. They are now dining on full branches of leaves in a screen house and will grow to the size of a sausage before summer ends. Several Cecropia Moth caterpillars are dining on Serviceberry and Maple leaves in plastic tubs. Our interns have named the largest one “Spike” and care for it as part of their day camp.

Over a dozen tubs filled with Monarch Butterfly caterpillars, eggs and chrysalises are piled on one cabinet in the office. These super-fussy caterpillars only eat milkweed, which has to be supplied in abundance as the caterpillars grow to be 60 times larger than their egg in the course of a couple of weeks.

These are caterpillars with a destiny. Not only do Monarch Butterflies migrate to Mexico, but these butterflies are also part of a breeding program to increase the local Monarch Butterfly population. Last year, the monarch population crashed to historically low levels. Audubon is working to help boost the local population, which already seems larger than last years.

Some of these Monarchs may also take part in our end-of-summer Monarch Celebration, with a family oriented Monarch Butterfly Festival on Saturday, Aug. 30, and the more adult-oriented “Monarchs and Margaritas” the night before.

Naturalists, volunteers, interns and even day camp groups have taken to scouring the milkweed patches in search of monarch eggs and caterpillars. Without help, most of these become food for ants, snails and other insects. By raising them indoors, more of the caterpillars grow up to be adults.

If you would like to see some of these caterpillars in person, stop in at the Audubon Center and Sanctuary at 1600 Riverside Road, near Jamestown. The building is open Monday through Saturday from 10 a.m. to 4:30 p.m. Check out the website at for more information on hours and programs.