My daughter, Kate, and I were cruising the aisles of a large, well-stocked garden center last week when we noticed rapid movement in a display of bee balm or monarda. The garden center was full of butterflies and small birds swooped in and out of the covered plant areas, but it was clear the movement was not typical of either one. Kate thought the winged creature sipping nectar from the flowers was a large bumblebee. I thought it was a hummingbird.
We were both wrong.
The fast flyer in question was a hummingbird clearwing moth or Hemaris thysbe, one of Nature’s great imposters. At about two inches long—give or take—the moth is of similar size to a hummingbird and shares common ground in eastern North America. The insects fly too fast for leisurely examination, but they are variable in color, sometimes olive-colored on top, with dark red to nearly black abdomens underneath. The wings, which are exceptionally hard to see when the moths are in flight, are mostly transparent, hence the common name.
Like a hummingbird, the clearwing hovers over individual flowers, inserting its long, slender proboscis or feeding tube into desirable blooms to get at the nectar inside. With wings beating many times per second, it darts through a stand of flowers, defying you to train your eye on it for more than an instant. If the day is still and you get close enough, you will hear a soft buzzing noise. This is another reason why it is often mistaken for a bee or a hummingbird. This resemblance is the result of a phenomenon called “convergent evolution”, a process that allows unrelated organisms, like clearwings and hummingbirds, which live in similar conditions to develop similar traits over time.
Unlike many common moths, clearwings fly during the daylight hours. Since their proboscises are adapted to ferret out nectar in tubular flowers, it stands to reason that some of their favorites include honeysuckle, the bee balm that my daughter and I noticed, lilacs, cranberry and blueberry blossoms, as well as thistles. Pink and purple flowers are favorites. I would suspect that members of the mint family, like salvia and catmint, might be considered clearwing delicacies as well. I have certainly seen hummingbirds frequent such plants.
Though you may never have noticed a clearwing, they are common throughout the eastern half of North America and show up in some parts of the Pacific Northwest. The fast flyers are fond of gardens and open areas, where they can find the most flowers. Adults lay green eggs on larval host plants including some of the clearwings’ food favorites like European cranberry and honeysuckle, plus plums and cherries. Though it seems counter intuitive, the green, horned caterpillars eventually pupate over the winter in hard brown cocoons just below ground level. In the northeast, where I live, the clearwing broods emerge and fly from April through August.
Clearwings were already winging their way around parts of this country in 1774, when a Danish zoologist/entomologist, Johan Christian Fabricius, described and named them. He named the species after Thisbe, one half of a pair of doomed lovers depicted in Ovid’s Metamorphosis. Shakespeare used the story as a basis of his Romeo and Juliet. In Metamorphosis, Pyramis, lover of Thisbe, finds her blood-stained scarf and assumes she is dead. Somehow, when Fabricius saw the dark red patches on the undersides of clearwings, he thought of Thisbe and attached her name to the moth. Classical scholarship has been responsible for many such christenings.
If you want to attract clearwing hummingbird moths, plant clumps of the flowers that they like and refrain from using pesticides in the garden. Look out for them during daylight hours whenever you are home. Chances are, if you watch careful and happen to be in the right place at the right time, you will see one flitting purposefully from plant to plant. It will be a rare treat.