Regular readers, and our long-suffering neighbors in Oak Bluffs, will know that over a span of 20 years, we’ve gradually converted most of our small yard into meadow, encouraging native grasses and wildflowers in an effort to make the yard as productive as possible for wildlife. The results may look a bit crusty, but the process has paid off: I’ve documented close to 400 insect species on our scant quarter-acre.
Most of those species have been common ones, as you’d expect. A few have been rare, at least locally; our “meadow” has produced a number of first-and-only records for Martha’s Vineyard. Some other species have been just plain puzzling.
Heading this last list might be the Northern flower moth, Schinia septentrionalis. The wings of this attractive moth, spanning about an inch, are mottled in rich tones of brown, and crossed by several bold, white bands. The hind wing, rarely visible in the field, is uniform slate gray, while long, hairy scales cover the thorax, giving the moth an amiable, fuzzy appearance.
Found not just on the Vineyard, S. septentrionalis has a puzzling geographic distribution. Southeastern Massachusetts, including Plymouth County, the Cape, and the Islands, stand out as the core of this species’ distribution, accounting for well over half the records I can find. But scattered records and some significant populations occur from Maine to the Midwest, to Arizona and New Mexico. One has to wonder if it is really the same species spanning that huge range of latitudes and habitats, or if our current concept of this moth includes multiple, not-yet-recognized species.
The common name of this attractive moth is apt: S. septentrionalis associates very closely with flowers, especially asters and goldenrods. Adults, active on the Vineyard mostly in September and early October, apparently take nectar from flowers, and often roost on top of flowers during the day, when they are easy to find, if present. The larvae, or caterpillars, of this moth reportedly feed on the flowers of a short list of aster species. (One small contribution I’ve made to our knowledge of S. septentrionalis was finding one of its caterpillars on goldenrod, possibly broadening the list of known food plants for the species.)
My first firm record for Northern flower moth dates back to September 2021, though I have vague recollections of seeing but not photographing it for several years prior to that. This year, the species has been downright common in the yard, reliably present, with sometimes as many as a half-dozen individuals readily visible.
The earlier presence of the species on Martha’s Vineyard is well, if rather sparsely, documented. Frank Jones, co-author of an important 1943 monograph of Vineyard and Nantucket moths and butterflies, collected several, and deemed the species (which he knew under the name Schinia brevis) to be “abundant” here in late summer. That assessment no doubt reflects the open condition of the much more agricultural Vineyard of those days; much of this moth’s habitat in Jones’ day is now oak woodland.
More recently, moth expert Paul Goldstein collected S. septentrionalis at Katama in 2013 (legs of that specimen have apparently been distributed to several labs doing genetic work on Schinia, which may eventually clarify exactly what Schinia septentrionalis is). But since then, our yard has been the only place on the Island where this once common but always conspicuous moth has been reported.
It isn’t the presence of this insect in my yard that puzzles me: While I didn’t have this species particularly in mind as I developed our meadow, the plants I’ve chosen to encourage happen to be ones the Northern flower moth appreciates, and it’s no surprise that the moth found them. What is really interesting to me is all the places where this moth does not occur! The flowers it’s using in our yard are abundant across much of the Island; why isn’t the moth?
Two lessons emerge from all this. First, the current popular interest in landscaping with native plants really has some solid basis. Insects are remarkably good at finding the resources they require, and if you plant a decent quantity of a native plant, the odds are good that you’ll soon find some of the insects that associate with what you’ve planted. You might not end up with S. septentrionalis. But you’ll get something else, perhaps something missing from my yard. So your native plants and my own can complement one another in supporting insect diversity.
But second, beyond basic outlines of presence and absence, we know very little about the natural world. Why is S. septentrionalis so regular in my yard, but so hard to find anywhere else on the Vineyard? Why is it found on the Cape and Islands, and in the Upper Midwest, but not in the vast swath of the Appalachians in-between? There are undoubtedly good reasons for all this. But only the moth knows what they are.
