Are spicebush swallowtails the cutest caterpillar?

By KATIE KOERTEN For the Gazette
March 21, 2021

Even if you love winter like me, you’re probably also heartened by the signs of spring that will be popping up soon. Skunk cabbage flowers are already poking up through the mud; red maples are swelling and will bloom soon. Red-winged blackbirds can be heard and turkey vultures are once again soaring through our skies. One early bloom I’ll be looking for in the next few weeks is one I overlooked for many years: northern spicebush (Lindera benzoin). Recently it’s become a friend I eagerly look for in mid-April.

A spicebush in flower. The delicate blossoms emerge before the leaves and are easy to spot in the woods. CONTRIBUTED/KATIE KOERTEN

Spicebush is easy to identify in early spring because its flowers bloom before its leaves emerge, and indeed before the leaves of any other deciduous trees and shrubs in the woods. In a bare-looking forest with only the needles of evergreens looking verdant, spicebush’s tiny poofs of greenish-yellow blossoms along slender, twiggy branches are relatively obvious.

Later, after the flowers are gone, the smooth, green, teardrop-shaped leaves will appear. By fall, beautiful red berries, or “drupes,” hang down from the branches of female shrubs, providing food for thrushes and other birds.

As an environmental educator and parent of a 5-year-old, most of my forays into nature are with young children. When I find a plant I’m excited about, like spicebush, I have found that I usually need to work a little harder to engage children with it than I would for say, a mammal, especially one that’s naturally cute and charismatic.

With plants, I try to find sensory experiences that will help children connect and relate. Jewelweed’s explosive seed pods, burdock’s sticky burs and greater celandine’s orange sap have all been memorable for kids I’ve worked with. They can easily recognize a plant again and again after they’ve had a fun experience with it.

Spicebush is fun because if you tear off a twig and sniff the fresh inner bark — there is a distinct aromatic scent, kind of like oregano. Smelling a new, pleasant smell is one thing that can help form memory and connection.

A spicebush swallowtail caterpillar. The eyespots are not eyes, but markings at the caterpillar’s tail end that may serve to deter predators. CONTRIBUTED/KATIE KOERTEN

Even more exciting for children than the smell is what can be found among spicebush leaves: spicebush swallowtail caterpillars (Papilio troilus)!

Spicebush leaves are the favorite food of these strikingly patterned larvae. The creature starts out as a tiny larva resembling brownish, tubular bird droppings. Then it grows a little bigger and greener, looking to me like a gherkin pickle. Its signature marking is its false eyespot pattern, which possibly helps it look threatening to enemies, more like a snake than a tasty caterpillar.

But to me, these large eyespots on such a tiny creature just have the effect of making it extra cute. They munch the leaves of the spicebush, producing a bed of silk inside the leaf that dries and contracts the leaf, making it curl upwards into a shelter. Searching for caterpillars in a spicebush plant with young children reminds me of an Easter egg hunt — but better. Sometimes a curled-up leaf will yield a caterpillar, sometimes it won’t, and that’s part of the fun!

Mid- to late summer is the time for finding spicebush swallowtail caterpillars in their host plants, northern spicebush and sassafras (Sassafras albidum). The Caterpillar Lab in Keene, N.H. advises: “Focus your searches along field and trail edges, and don’t overlook the tiny sapling plants at your feet. Spicebush swallowtails often lay eggs on knee- and even ankle-high plants. Never look for the caterpillars themselves, instead search for upward-rolled leaves with no outward sign of silk ties.”

Last summer my daughter and I found a sassafras tree at the beginning of a long hike. Instinctively I began scanning the tree for a telltale curled-up leaf that would signal that a spicebush swallowtail caterpillar was within. Sure enough, we found a curled-up leaf and one of the little cuties inside. We were delighted and decided to scoop it up on our way back down the mountain and take it home to put on one of the young spicebushes in our yard.

However, when we returned on the way back down, the caterpillar was gone from the curled-up leaf. We searched and searched, but couldn’t find it again. We were, and remain, mystified at how the creature could have relocated so quickly. We’re hoping to find more this year.

This April, look for those poofy, yellow-green blooms on a shrub in the understory. Take off a tiny twig and take a sniff to confirm you’ve got spicebush. Then come back frequently to visit, and search for spicebush swallowtail caterpillars.

Katie Koerten is an environmental educator at the Hitchcock Center for the Environment. For more information about the Caterpillar Lab, visit www.thecaterpillarlab.org.

Earth Matters has been a project of the Hitchcock Center for the Environment for 12 years. In response to the COVID-19 crisis, the Hitchcock Center has adapted its programming and launched a new sliding-scale fee structure for families facing financial challenges. To help the Hitchcock Center survive this difficult time, please make a donation at hitchcockcenter.org.

Earth Matters, written by staff and associates of the Hitchcock Center for the Environment at 845 West St., Amherst, appears every other week in the Daily Hampshire Gazette. For more information, call 413-256-6006, or write to us.

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