Across the years that I’ve been studying the Vineyard’s Orthoptera (grasshoppers, crickets, and katydids), the first of August has emerged as special date. Invariably, within a couple of days on either side of that day, a wide range of Orthoptera abruptly reach maturity.
If you can see them, it’s easy to tell when one of these insects hits adulthood. After growing through a series of five or six stages as a nymph, resembling the adult form but smaller and with only stubs for wings, an Orthopteran conducts a final molt and takes adult form: full size, wings fully formed (if the species has wings), and sexual apparatus intact.
But you rarely see the insects in this order; they’re masters of concealment, every last one of them. Happily, along with maturity comes, at least for the males of some species, the ability to produce sound. Rubbing its wings together, or scraping its thighs against its wings if it’s a grasshopper of certain species, a newly matured male “stridulates” to announce its presence to potential mates.
The first of August, then, marks the time when the summer’s Orthoperan chorus kicks into full swing. Nights, and sometimes days, vibrate with the buzzes and trills of amorous crickets and katydids.
Most numerous and easiest to find among these insects are the ground crickets, represented on the Vineyard by three or four species of tiny hopping insects that associate closely with grassy areas. This proclivity makes them abundant in the yards and parks around human habitation. Indeed, a couple of our ground crickets figure among the very few types of wildlife that seem actually to prefer such human-modified habitats, and it is a rare thing for me to walk past a yard in August and not hear at least a species or two of this group hard at work.
Perhaps the most ubiquitous member of this group, in settled neighborhoods, is the Carolina ground cricket, perhaps our smallest species. Male Carolinas give an unceasing, soft trill with a slightly dry or woody quality: One field guide transcribes the sound as “Riiiiiiiiiiiii …,” and that’s about right. This species may be less fond of grass than its relatives, and more fond of herbs and forbs; in our yard, I typically hear them calling from deep within clumps of marjoram in the herb garden.
Two other ground crickets, Allard’s and tinkling, sound much alike, giving a sustained, very fast series of high-pitched notes, with perhaps 10 to 20 notes per second. As with the Carolina ground cricket, a male will often keep his song going without a break for many minutes, no doubt impressing females of his species with his stamina.
The final member of this group that I’ve found on the Vineyard is the striped ground cricket, which is a bit of an outlier in preferring natural habitat to yards and gardens. This insect generally occurs near water, either brackish or fresh. You can hear these crickets easily from the bike path along the Beach Road between Oak Bluffs and Edgartown, where they call from the upper edge of the salt marsh in a steady series of buzzy “zip! zip! zip!” notes.
Ground crickets resemble the more familiar field crickets — those large, black crickets that turn up in basements in late summer and sing with loud, iconic “crick! crick crick!” But compared with the length of our two nearly identical field cricket species — roughly three-quarters of an inch — ground crickets are markedly smaller; our largest tops out around a half-inch long, and some adults of some species don’t even crack a quarter-inch.
In part because of their tiny size, ground crickets are fiendishly hard to spot, even when you’re within inches of a singing male. They spend most of their time snuggled down in that grass thatch or leaf litter, or around the base of the stems of a bushy herb or flower, where their brownish coloration helps them hide. At the least sign of disturbance, they dig even deeper into concealment.
With powerful hind legs, ground crickets jump like little artillery shells if they have to, arcing amazing distances for such small, chubby insects. But leaping is a last resort. The robust, heavily spined hind legs seem at least as well adapted for pushing back against vegetation as for jumping. Thrusting backward with those limbs, a frightened ground cricket drives itself deep into the vegetation it’s hiding in. Feel free to try, but they tunnel faster than you can search, and once you’re flushed one, you aren’t going to get a look at it.
I confess I rarely try to spot these elusive insects; even when I do, the species are so similar I can’t ID them with any confidence. But their songs distinguish them reliably. And the inescapable nature of those calls in late summer, once you’ve learned what to listen for, is good reminder of how numerous an insect can get while still being impossible to spot!