Englishman John Edward Smith was a groupie of sorts.
It wasn’t a band, athlete or actress that held his interest. It was quite a different time in the late 18th and early 19th centuries, when he was fervently following the object of his desire.
Obsessed with Swedish naturalist and creator of classification Carl Linnaeus, Smith borrowed money from his father to purchase the entire compendium of Linnaeus’s work, a collection that included books, manuscripts, and specimens. The loan was 1,000 British pounds, which in today’s dollars would be almost $200,000.
Smith went on to create the Linnaean Society to honor his hero, and was president of the organization from its establishment through Smith’s death in 1829. His wife, Pleasance, might have made a tidy profit on the sale of the collection after her husband’s death, when those resources were sold for three times their purchase price to the Linnean Society. The money was likely needed, since Pleasance, a writer, editor and success in her own right, lived to over 100 years old.
Of course, Smith also collected, studied and named species before his death. Over 140 unique organisms were purportedly named by him; one remains something of a unicorn.
The Unicorn Prominent is a common insect found throughout North America. Smith originally named this moth Schizura unicornis but, more recently in 2021, research concluded that it actually belonged in the Coelodasys genus, though it retained the unicorn epithet.
Unicorn describes not its rarity, but its horns, one of a few on the caterpillar’s undulating body. The largest of the horns function much like Spiderman’s wrist shooters, but in the caterpillar’s case, it is formic acid (not a web) that is shot out of the horn. This acid serves as protection, harming any predators coming its way.
People can be affected by this substance, which reportedly causes blistering on human skin that is accompanied by burning and stinging of the affected area. Perhaps not the friendly unicorn you may have been imagining, but necessary for species survival.
These caterpillars also protect themselves through their coloring. Their bodies are mostly speckly brown, with a bright green segment. This shading mimics leaves browning in the fall, and the green blends in with leaves during the growing season. The shape of the caterpillar is as effective as its camouflage, because the creature resembles a curled-up leaf edge.
While you may not notice these prevalent prominents, they make their presence known through their appetites. Feasting on a variety of species that include apple, hawthorn, elm, aspen, hickory, birch and willows, damage to the foliage of these species can be observed. In large numbers, these caterpillars can do some damage and even kill those affected trees.
The caterpillar I observed on the concrete deck outside my office was on the ground and not bothering any flora. It was likely preparing to overwinter, which it will do in a white, flimsy cocoon beneath the leaf litter. As many insects instinctively know, a pile of leaves provides a safe winter home until spring, when it can emerge in its next form. So, to overzealous yard tenders, I say please leave the leaves for all of those overwintering organisms.
The moth that will emerge come spring is quite nondescript. Not fancy or overly noteworthy (except to John Edward Smith), it may just fly away and live out its short life, focusing mainly on finding a mate and reproducing for the next generation.
Perhaps it will serve important functions as a nectar-drinking pollinator. Or maybe it will become a meal for a bird or other hungry creature — fulfilling its own niche in the cycle of life, and embodying the truism that, if unicorns don’t exist, they probably should.
Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.