“If you like fall,” one of my insect-enthusiast friends recently griped, “you’re basically saying that you like watching insects die slowly.”
It’s true. There are certainly positive aspects to a Vineyard fall: vibrant foliage, bird migration, fine sunny days, fewer people. But if you’re focused on insects, it’s a season of repeated loss, as one species after another disappears.
It’s a protracted process, though, unfolding over a couple of months, as hardy species persist long after their more tender relatives succumb. A few cricket species are still calling, and will be with us through this month or even into early December. A few cold-weather specialists, like winter moths and winter crane flies, are still climbing toward their peak abundance, as late fall or early winter are their high season. But for the most part, the bugs are done.
Many insects, perhaps most of them, simply disappear. I can’t possibly keep track of when I’ve seen the last member of every species. But over and over again, it occurs to me that it has been a long while — though I can’t recall how long — since I’ve seen a locust borer beetle, or a Peck’s Skipper, or a robber fly of any kind. There was a final one, of course, but I failed to notice it.
The demise of other species, though, plays out in slow motion over a period of weeks. I still hear, for example, tree crickets in my yard — narrow-winged tree crickets, Oecanthus niveus, giving short, pulsing trills. But as the air cools, the calls grow less plentiful, slower, and more labored. On the coldest nights we’ve had, producing sparkles of frost by sunrise, they don’t call at all, and I think they’re gone. But when it warms again, the calls resume, fewer with each such cycle and more ragged. When this species doesn’t bounce back after a frost, I’ll notice, giving a precise last date for the year in my records.
Red-legged grasshoppers, abundant here into mid-October, have likewise grown sparse. This species doesn’t call, though it shows its age in other ways. Senescing individuals grow drab and brownish, losing their brightest colors, and they become listless and finally unresponsive. Formerly, each step through my tiny meadow produced a burst of four or five of these grasshoppers leaping away, frantically flapping their inefficient wings, landing with a satisfying smack on a stem or fence post. Now it takes several steps to flush out a single one, and in another week or two, even a careful search will produce none at all.
Fortunately, I don’t grow attached to individual insects, and that keeps the season from being too depressing. The adults may be gone, but in some form or another, I know the next generation is lying in wait. For the tree crickets, eggs have been embedded in plant stems; for the grasshopper, they’re in the ground, placed there by a female grinding the tip of her abdomen into the soil. In both cases, warm weather next year will trigger the hatch of a new population.
Every species has its plan: While overwintering in egg form is probably the most popular method, larvae, pupae, or adults may also overwinter, depending on the organism. A few, notably some butterflies and dragonflies, won’t even try to survive winter here; this season’s adults will either migrate south or simply die, and those species will recolonize our region next year, expanding from southerly populations below the latitude of hard frost. There’s a certain amount of consolation in this: I’m fascinated by the complex biology involved in surviving winter, and finding overwintering forms will provide a certain amount of entertainment during the coldest months. Some species will be active on the warmest days; others I’ll turn up while poking around under leaf litter or flakes of bark.
I won’t be the only one looking: Dormant or semidormant insects and spiders, in all of their developmental stages, are a dietary standby for the songbirds that winter here, which may devote hours every day to searching for tiny prey. But enough survive to repopulate the world in spring.
In a way, I even appreciate the end of the season. I’ll have time now to sort through photographs (I kept several thousand from this past season), trying to identify species that had me puzzled, and moving photos into species or genus folders. I’ll have time to organize written notes, update master lists, and even start studying field guides so I’ll be ready to tackle some new groups of insects next season. I’ll draw up a list of priorities for the year, questions to try to answer, species to search for, locations that I feel need more exploration.
But still, the spread of silence and stillness in the natural world saddens me. They’re not quite friends, but insects brighten my summers with their variety, their amazing adaptations, and their vitality. I hope they sleep well.
