I’ll begin this column with a century-old prediction, hazarded by the entomologist Albert Pitts Morse (1863-1936) in his 1920 monograph, “Manual of the Orthoptera of New England.”
In his extensive travels to survey the region’s Orthoptera, Morse found the small katydid species Conocephalus saltans only on Nantucket, where it was “not uncommon at widely separated points on the sandy moors in early September 1913.” (Data in the iNaturalist platform show that the species persists on Nantucket to the present day.) But with a good eye for ecological parallels, Morse urged that “search should be made for it on Martha’s Vineyard.”
With my strong interest in the Vineyard’s Orthoptera, I was acting on Morse’s prediction even before I became aware of his monograph. I first encountered C. saltans in 2017 in Lexington, where a small but evidently persistent population occupies a small meadow on a sandy morainal hillside. Conditions there reminded me of the Vineyard, and reasoning exactly as Morse did, I felt it likely that the species occurred here. But while I managed some tantalizing sightings over the years, all ultimately proved to involve odd-looking individuals of a related species, Conocephalus strictus, which is quite common here.
Then on August 6, local naturalist Sharon Britton photographed an odd-looking katydid in West Tisbury, creating an iNaturalist observation from the photos. At the time, I figured it was probably the expected C. strictus. But it looked strange enough that I didn’t propose an ID. A few weeks later, Gracie Catanzaro, a skilled naturalist in Virginia whom I know by her iNaturalist username, graytreefrog, weighed in, identifying it as C. saltans.
An active discussion ensued on iNaturalist. The challenge was that Sharon’s katydid, a male, was still immature, which vastly complicates katydid ID because coloration and the structure of body parts can change as individuals mature. But graytreefrog’s opinion was enough to get me out to the location where Sharon had found her katydid. Almost immediately, I found and photographed two females and a male that were unambiguously adult C. saltans. Graytreefrog had been right, and so had Albert Pitts Morse. C. saltans became the 76th species of Orthoptera known from the Vineyard.
While the species is sparsely distributed in Southern New England, with that population in Lexington apparently marking the extreme northeastern limit of its documented range, Conocephalus saltans is more common to the South and West. Records extend west to, and even west of, the Rocky Mountains, northwest into the prairie provinces Manitoba and Alberta, and south and east through the Midwest to Texas and Louisiana.
With a body about an inch long, C. saltans generally displays brownish coloration, quite different from the green of its closest relatives. And as with katydids generally, both males and females have distinctive external genitalia extending from their abdomens. But the most salient feature of the species may be its near-winglessness: Females are normally flightless, showing just tiny vestigial wing buds, and males have only enough wing to stridulate (that is, call by scraping their short wings together).
It is typical of Morse’s careful study that he gave some thought to the circumstance of a flightless insect occurring on an Island such as Nantucket. How did it get there? Morse’s explanation, and I find it compelling, is that it has been there for a long, long time. He speculates, “In an earlier geological time, a great sandy plain bordered the Atlantic Seaboard from Virginia to Newfoundland, [allowing] characteristic plants and animals to spread far to the northeast.” Isolated populations of species such as C. saltans, Morse believed, are relics of this broad distribution, persisting in especially favorable spots amid a now-eroded and fragmented landscape.
This understanding is now broadly accepted by ecologists studying our region. As the last Ice Age waned, there was a period of centuries or even millennia during which a warming climate allowed invertebrate populations to rebound northward. Though the icecap was shrinking, enough water remained frozen to maintain low sea levels, and what we now know as Martha’s Vineyard and Nantucket were areas of morainal hills still connected to the mainland. Much of today’s ecology of our region still reflects the dispersal and colonization by plants and animals during this period, before erosion and rising sea levels isolated the islands and constrained the arrival of additional species.
It’s worth noting that ideas of epochal change in the world, and even the notion of evolution, were far from universally accepted during Morse’s lifetime. The famous “Scopes Trial,” for example, in which high school instructor John Scopes was convicted of teaching the theory of evolution in violation of Tennessee state law, took place in 1925, five years after Morse’s monograph appeared.
Morse’s description of the habitat preferences of this katydid also remains accurate. He found it in dry, sandy habitats, often dominated by little bluestem grass and wild indigo, mixed with woody vegetation such as huckleberry. And his description of C. saltans as sparsely distributed, though sometimes fairly common where it does occur, accurately describes the present-day status of the species.
So this interesting insect has presumably been hiding in plain sight on Martha’s Vineyard, as Morse predicted. It simply took a century, some astute fieldwork by Sharon Britton, and the power of modern methods of nature study to prove him right.
