Wild Side: Orthoptera news

New species are making homes here.

Pine tree cricket, Oecanthus pini. —Matt Pelikan

We’re still in the peak season for orthoptera — crickets, katydids, and grasshoppers — and the past few weeks have shown that there is still a lot to discover.

First, on August 28, a small, greenish cricket clinging to the screen of the front door of the Nature Conservancy’s office off Lambert’s Cove Road proved to be a pine tree cricket, Oecanthus pini — a species I’ve long suspected was present but had never been able to nail down. This is the sixth time the exterior of that building has produced a first Island orthoptera record! The setting is wholly unremarkable, and my success there is a reminder that frequency of coverage can be as important as quality of habitat for finding wildlife.

More significant may have been the near-simultaneous appearance of true katydids, Pterophylla camellifolia, at two down-Island locations. Philosophically, of course, it’s impossible to prove the absence of something, so I can’t be certain that this species wasn’t here before. But it’s a large insect with a loud, persistent call, and if it were anything like common here, I’d surely have noticed it. Odds are good this species has just arrived on the Vineyard.

The event was not unexpected; formerly a more southern species, pterophylla has, over the past few decades, marched steadily northward into southern New England, and is now widespread on the Massachusetts mainland. Its distinctive call — sometimes transcribed as “katydid, katydid,” but registering to my ear as “cha-cha-cha, cha-cha-cha” — has grown into a familiar feature of the mainland’s nocturnal soundscape. Sometimes the call has two syllables, or four, rather than three, but the raspy tone and emphatic quality are constant and unmistakable.

Given that this species is often common in heavily settled areas, and that thousands of cars, trucks, and trailers arrive on-Island from such areas every season, it was inevitable that this species would eventually hitch a ride to the Vineyard. It’s also possible for a species like this to make it here under its own steam; heavy-bodied, they’re not exactly masters of the air, but they can fly, and no doubt cross long distances if aided by a favorable wind (and a desire not to land in the ocean).

In any case, the first whiff I’ve had here of true katydids came from a Sept. 6 post in a Vineyard birding Facebook group. Nancy Weaver, an alert observer with at least one first Island orthoptera record to her credit already, captured a cell phone video of what turned out to be the call of this insect from a private development in Oak Bluffs. With further assistance from Susan Travers Desmarais, I was able to locate the site, and heard at least 15 katydids calling in the neighborhood.

Commenting on Nancy’s Facebook video, Brian Athearn mentioned hearing something similar around the lower end of Lambert’s Cove Road, in Vineyard Haven. Entomologist Paul Goldstein recently confirmed the identity of Brian’s calling insects, establishing the presence of a second true katydid population on the Island.

Finally, another long-elusive species with a distinctive call, the snowy tree cricket, turned up at two widely separated locations: downtown Edgartown on the night of Sept. 1, and then the parking area for Eastville Beach on Sept. 7. Again, the previous status of this species is uncertain; it could have been absent, or just scarce enough so I managed to miss it. But it’s here now, and again, the locations seem consistent with human-aided arrival.

With these changes, the number of orthoptera species recorded on the Vineyard now stands at a respectable 52. I should be clear that the level of documentation varies, from unambiguous specimens or photographs at the solid extreme to identifications (as with the true katydid, so far) based solely on calls, and falling short of what a real scientist would accept as certain. Moreover, a few species known only from old records, and possibly absent now, figure in that number. But the list reflects my standards as a committed naturalist, and if it may contain a few errors, it at least gives a fair sense of the surprising diversity of this group on the Vineyard.

After about ten years studying orthoptera, I’m ready for things to calm down. It’s not that I’m tired of these excellent insects; far from it! But there are a lot of other groups of wildlife I’d like to direct my time and attention toward, and I wouldn’t mind much if things calmed down enough so that orthoptera could morph into another background interest, rather than an active project.

But questions keep coming faster than answers, and things that I think I know keep turning out to be wrong. If there’s one thing I’ve learned about this group on Martha’s Vineyard, it’s that the roster of what occurs here is in constant flux. A truly stable checklist for the Island will never exist.