Wild Side: Pygmy grasshoppers

Leaping into the State Forest this time of year.

Crested pygmy grasshopper, a tiny and enigmatic resident of the Vineyard’s sandy barrens habitats. The species has a wide range of variations in color. — Matt Pelikan

One of the stranger insects I’ve encountered on the Vineyard is Nomotettix cristatus, sometimes called the crested pygmy grasshopper. Pygmy grasshoppers in general compose a family of their own, Tetrigidae, quite distinct from typical grasshoppers

As the name suggests, pygmy grasshoppers are tiny. In the case of nomotettix, large females may reach a centimeter in length; males, invariably smaller, may be as short as six millimeters, or about a quarter-inch.

These dimensions alone would be enough to make these insects elusive, but their coloration makes them even harder to spot. Nomotettix varies quite widely, from reddish-brown to gray to a combination of the two. Some individuals are solid in color; others have odd, triangular black-and-white marks on their sides. But in any case, the coloration blends in well against the sand, fine gravel, and fallen leaves that these grasshoppers seem to prefer.

If you think in terms of the population as a whole, the variation in color and pattern probably works as insurance, guaranteeing that no matter what the season or how conditions change, some percentage of individuals remain protectively colored.

Like all the members of the pygmy grasshopper family, nomotettix is characterized by a long extension of the pronotum — the top surface of the insect’s thorax — backward over the wings and abdomen. This feature gives these chunky insects a clean, compact outline; they look oddly manmade and mechanical.

They jump like it, too. Nomotettix possesses massive femurs, or thighs, on its hind legs. And the musculature within the exoskeleton of those femurs is powerful enough to launch these tiny insects a solid two feet in one leap. Up close, you can hear a faint “click” as the legs of a leaping nomotettix snap straight.

The basic life cycle of pygmy grasshoppers is well known. Living through the winter in adult form — a trait separating Tetrigidae from typical grasshoppers, which generally overwinter either as eggs or at an immature stage — nomotettix mates in the spring. When they hatch, the young, or nymphs, resemble adults but are even smaller. By late autumn, they’ve matured and prepare to overwinter and start the cycle again.

Behavior adds to difficulty of finding nomotettix. Even when I come across one in the open, it invariably sees me before I see it — and when frightened, this grasshopper is not hesitant to launch itself toward cover. A good percentage of the individuals that I notice catch my eye as they make one long bound for safety, disappearing for good because my eyes can’t follow their fast trajectory.

Given that adults or near-adults are present throughout the year, it’s interesting that virtually all of my records for nomotettix fall into a brief window in early spring, basically the final three weeks in April. I have only one fall record, from mid-October, and only one late winter record (from March 16 of this year). All my records are from Correllus State Forest.

I don’t think my own behavior as an observer fully explains this pattern: I spend a lot of time throughout the warmer months in places where I know nomotettix occurs, but never see it. And on some unseasonably warm days in winter, I’ve looked very hard for this species, again in known locations, with no success. My few records from the extremes of the year — March and October — have involved individuals that I stumbled over while rummaging through leaf litter in search of something else entirely.

I surmise, then, that early spring is a time of heightened activity for these insects, and possibly a season that tends to brings them more into the open. (The ones I find in spring mostly turn up on nearly bare sand on State Forest fire lanes.) Perhaps they spend April wandering about seeking to find or attract mates, inadvertently making themselves easier for me to find.

The rest of the year, I expect they live in deep concealment, their drab coloration matching dead leaves and making them almost undetectable. Feeding on lichen, roots, and decaying vegetable matter, pygmy grasshoppers probably find all they need in the leaf litter. In winter, I doubt they move at all, probably spending all their time semi-dormant under debris or at the base of clumps of grass.

One result of the cryptic nature of this species is that I haven’t got the faintest idea how common it actually is. I don’t think I’ve ever seen more than five nomotettix in a day. Over the course of a typical year, I’ll likely find fewer than a dozen, despite the fact that I look hard for this species, which is a favorite of mine.

But this apparent scarcity may just reflect my inability to spot them. The fact that I’ve turned up a couple of individual while basically scratching through dead leaves at random might suggest that the species is actually pretty numerous. It would take intensive research — a concerted campaign to trap all the individuals in a defined area — to answer the question of abundance.

There remains, clearly, a lot to learn about this species. But nomotettix is such an odd and distinctive creature that I’m glad we’ve become acquainted.