Wild Side: How long will it stay?

My first Island sighting of the grasshopper Pseudopomala brachyptera leaves me wondering how much longer our habitat will support it.

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The past couple of weeks have been fine ones for me, replete with interesting wildlife sightings and opportunities to explore new or inaccessible areas. It’s hard to pick one single discovery as the high point of this period, but a leading candidate would have to be my first Island sighting of the grasshopper Pseudopomala brachyptera.

Also known by common names such as bunchgrass grasshopper or short-winged toothpick grasshopper (“brachyptera” means “short-winged”), this species is one of the strangest-looking insects I’ve ever encountered. Though recognizably a grasshopper in overall structure, it’s an elongated insect with sword-like antennae and, in most cases, only rudimentary nubs for wings. (A small percentage of the population does have complete wings, and these individuals are reportedly capable of weak flight.) Generally light brown in color, sometimes mottled with faint darker markings, this is a species of dry grasslands on lean, sandy soils. It’s a perfect match for the Vineyard sandplain.

And yet it appears to be rare here. It has been on my “most wanted” list for more than a decade, and I’ve searched hard for it in habitats that seemed to me like perfect candidates to host it, with no luck until June 17.

Going back a century or so, the brilliant amateur entomologist Albert P. Morse deemed P. brachyptera “not uncommon [at] many localities in Connecticut and Massachusetts, including the island of Martha’s Vineyard.” More recently, the species is known here from a total of three specimens taken at two south shore locations in 1992. I came across those specimens, not yet identified, while I was working for the Nature Conservancy, ID’d them, and, fascinated by what Morse calls “its singular, almost grotesque, yet graceful shape,” began my effort to relocate this grasshopper on the Island.

Pseudopomala, usually lacking wings and not even particularly deft at leaping, reposes great confidence in its ability to be invisible. This grasshopper often perches upright along a twig or stem, blending right in as if part of the plant. In a characteristic posture, it often splays its gawky hind legs out to enhance the stick-like effect. Whether disturbed or merely moving about the vegetation to forage, it prefers to walk or crawl rather than jump. And when alarmed, it tends to sit tight, not moving except to swing around to the opposite side of the stem it’s on from whatever the threat is.

These habits no doubt account in part for my difficulty in finding this species. My standard grasshopper search method is to walk at a moderate pace through promising habitat, flushing grasshoppers, watching where they land, and then approaching more cautiously to get a good look and, hopefully, photographs. A species that hides rather than jumps when disturbed is easily missed by those tactics, and in retrospect, I’m horrified to think how many bunchgrass grasshoppers I may have walked within feet or inches of without seeing.

I may also have been misled by my understanding of the preferred habitat of this insect. Between the common name “bunchgrass grasshopper” and species accounts that play up Pseudopomala’s association with little bluestem grass, I’ve focused my search on grassland remnants strongly dominated by this ecologically important grass. But the habitat I found it in in Edgartown, and in places where I’ve found it on the mainland, was actually quite diverse. Little bluestem was present in all cases, but the species mix included a wide range of other grasses, herbaceous plants, and even low shrubs. I may have been barking up the wrong tree all these years.

Even so, 12 years into my obsession with grasshoppers, I’ve gotten pretty good at finding them. And I’ve spent a huge number of hours in habitat that’s suitable for P. brachyptera. I may well have overlooked some individuals. But on balance I feel this species truly must be rare, local, and likely declining on Martha’s Vineyard, or else I would have run into it before now.

Back in Morse’s day, the much more open landscape of the Vineyard surely offered this and other grasshopper species vast tracts of well-connected habitat. Since then, residential development and the gradual regrowth of woodland in what was formerly pasture has greatly reduced the opportunities for dry grassland species like P. brachyptera. With its sluggish habits and its inability to fly, the bunchgrass grasshopper probably exists today just as small, local populations strongly isolated from each other. Sadly, this is to say, it is probably a species at high risk of being extirpated from the Vineyard.

So my rediscovery of the species on Martha’s Vineyard has a melancholy overtone. Will I, or anyone else, ever see another member of this species here? Or will P. brachyptera, along with who knows how many other species with similar ecological needs, blink out from one pocket of habitat after another until it is completely gone?