Seeing as it’s June, the most popular month for weddings, it only seems fitting that we talk about…underwing moths.
I’m sure you’re probably thinking, “Moths? Eww. Aren’t they the critters that eat my wool sweaters and hatch out of my birdseed?” Well, yes, but that’s a topic for a whole different column. Many other fine species—more than 11,500 in North America alone—live among us and lead wonderfully intricate lives full of mystery and intrigue. The underwings (Catocala spp.) are no exception.
Let’s start with that fancy genus name. Hidden therein, disguised under Greek roots, lies a clue to the underwings’ great claim to fame. Cato is derived from kato, which means below or behind. And cala is from kalos, for beautiful. Taken literally, underwing moths have a beautiful behind, but what the word really refers to is the moths’ hindwings—the ones that sit, completely concealed, underneath the top, or forewings, when the moth is at rest.
Sitting quietly on a tree trunk, underwing moths are some of our area’s best-camouflaged critters. Their elaborately marked forewings look just like bark; in fact, some even manage to look like bark speckled with lichens or moss. But the real show starts when an underwing is disturbed and/or takes flight. That beautiful behind is revealed and, depending on species, can flash brilliant hues of yellow, orange or red, as well as black or white.
Such an eye-catching display is startling to say the least. For an underwing being pursued by a predator, that surprise splash of color may buy the moth the split-second it needs to avoid capture. Or, it may bring interested naturalists closer, in hopes of making an identification.
You see, another cool thing about underwing moths is their common names. Long ago the Swedish taxonomist Carl Linnaeus came up with the idea of naming underwings using a theme of women and relationships. He gave us the names of the European species C. nupta, (“marriage”) C. pacta (“agreement”) and C. sponsa (“wife”). Other scientists followed suit, and today we have names like the girlfriend, darling, sweetheart and betrothed; the bride, once-married and old wife; and the tearful, gloomy, inconsolable and widow underwings.
Some are named after women noted for their beguiling ways, notably Cleopatra and Delilah. And some are named after Shakespearean characters, such as Ophelia, Miranda and Desdemona.
Want to take a closer look? Sneaking up on an unsuspecting underwing is harder than it sounds. For one thing, if they’re resting on tree bark, they’re next to impossible to spot—even though their beefy bodies may measure nearly 2 in. in length. Luckily, they at times may take refuge in picnic shelters in wooded areas, or come to rest on a fence post or rock where their camouflage isn’t as effective.
For another thing, underwing moths have extremely good hearing. They’re very hard to approach and often take flight long before you’re close enough to make even a tentative i.d. Their “ears,” tympanic membranes on either side of the thorax, are quite sensitive and can pick up sound even in very high frequency ranges; it makes things tough for us nature nerds, but it’s definitely a handy skill for these moths, who frequently must elude hungry, echolocating bats.
In fact, if you want to try a little experiment, wait until near dusk, then head out to a nearby wooded natural area like St. Charles’ Norris Woods or Campton Hills Park. Bring a set of keys along and, when you spot an underwing in flight, give the keys a shake. Supposedly the jingling sounds simulate those of bat sonar waves and will cause an underwing to drop from flight in defense.
If anyone asks what you’re doing, just say you’re having a little fun with your sweetheart. Or darling. Or old wife…
Pam Otto is the manager of nature programs and interpretive services for the St. Charles Park District. She can be reached at potto@stcparks.org or 630-513-4346.