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Sometime in the next few weeks, greater Washington is due to be afflicted by a noise even less coherent and more irritating than the bombast that’s been emerging from Capitol Hill. And unlike the 100-days rhetoric, we won’t be able to escape the endless droning by changing the channel from CNN to Melrose Place.
Winging its way from the air rather than the airwaves, the latest assault comes courtesy of Mother Nature, who in one of her more whimsical moments dreamt up the 17-year cicada. This creature has the dubious distinction of being one of the largest, loudest, weirdest-looking insects on the continent, with a life cycle that still baffles scientists: 17 years as a slug underground, then a month or so of freedom to fly about, fornicate, and vociferate.
But wait a minute, you protest: There’s no way it’s been 17 years since the last cicada siege. You were probably drinking chardonnay at Afterwords, and could hardly hear yourself think about public policy, what with all the noise coming from the trees. What’s more, you couldn’t walk down the street without crunching a corpse or two. It was really gross.
It’s true. It hasn’t been 17 years since the last infestation; it’s been only eight. In 1987, in a bizarre rite of spring, billions of cicada nymphs, their eyes gleaming red, their bodies a ghostly white, struggled up from the earth where they had been entombed for years. In response to a summons only they could hear, they clawed their way onto the nearest tree trunks and began their metamorphoses. Some never gained a foothold, and died. Others failed to molt; they too died. But if all went well, within an hour each nymph would shed its pale skin, develop a new dark one, unfurl its wings (transparent, save for a trace of reddish-orange), and begin its brief adult life.
But that 1987 population was only one brood of cicadas. There are, scientists estimate, about 15 separate broods, each with its own unique geographic distribution and cicadan rhythm. Which means that almost every year, somewhere, a brood makes its rare appearance. This spring, it’s showtime for Brood I, whose range reaches from Long Island to Tennessee. Brood I is known to be far smaller than 1987’s Brood 10, but until the cicadas actually emerge, no one knows exactly where they’ll appear or how numerous they’ll be.
Though cicadas are remarkable insects, very little research has been done on them. For one thing, explains Doug Miller, an entomologist with the United States Department of Agriculture, it’s hard to build a scientific career on a creature that operates on such a leisurely schedule. Even a student determined to hole up in grad school as long as possible would be daunted at the thought of spending 17 years on a dissertation. In addition, cicadas have no agricultural significance, which means that crop growers are disinclined to fund studies.
So scientists like Miller and his counterparts at the Smithsonian are mostly reduced to fielding phone calls when cicadas emerge. There’s nothing to worry about, they tell the frightened callers, since cicadas don’t sting or bite. (Though in their late nymphal stage, when they have sharp talons, they can damage the digestive system of cats, which go into feeding frenzies over them.) But most calls, says Miller, are prompted more by curiosity than concern. “They want to know more about these strange creatures. What are they, and where do they come from?”
In brief, 17-year cicadas are a genus unique to the United States. And though their emergences made early Americans feel that a plague of Biblical proportions had been visited upon them, the cicada is in no way related to the ravenous locust of the Bible, which could reduce a garden to a desert in a matter of hours. The locust is a species of grasshopper. The cicada, on the other hand, is a member of the Homoptera order, which includes such wimps as aphids and mealybugs.
Though cicadas feed off trees, they are a sucking rather than a chewing insect; they get their nourishment not from leaves, but from the sap, which the tree can easily part with. The only trees at risk from cicadas are saplings (particularly fruit bearers), whose branches can break under the weight of the eggs the female lays. Tying cheesecloth around young trees is usually enough to protect them.
Nor are cicadas harmful to humans. “They won’t dive-bomb you,” says Miller. As for the noise they make, some people find it quite pleasant. In some countries, cicadas were once kept in cages, the better to sing for their keepers.
But melody or cacophony, one thing is indisputable: The cicada is LOUD. A single cicada can be heard a quarter of a mile away. A chorus of cicadas can produce a din that registers 100 decibels—almost the equivalent of a jackhammer. Like a heavy-metal musician, the cicada runs the risk of destroying its own hearing. But unlike its human counterpart, the cicada has a built-in protective mechanism: While it sings, it collapses its eardrum, blocking out most of the noise it makes.
Only male cicadas go in for making music (or noise), which led the Greek writer Xenarchus to quip, “Happy are cicadas’ lives, for they all have silent wives.” The sounds are produced by two membranes in the male cicada’s thorax, which he vibrates by lifting his abdomen. Unlike most other insects, including the common or “dog day” cicada that appears in late summer every year to announce the sunset, the periodical cicada drones from dawn to dusk.
Though the tonal qualities of the sounds vary from species to species, all periodical cicadas have a repertory of three works—a congregation song, a courtship serenade, and a disturbance sound the insect makes when it feels threatened.
Since the adult cicada needs very little food, it spends most of its time singing and having sex. Cicadas begin mating within a week after attaining maturity, and the larvae follow in about six weeks. The female lays as many as 600 eggs in a pocket she creates in a twig. Under their weight of fecundity, the twigs sometimes snap off and fall to the ground. If that happens, the hatched nymph is in a better position to burrow underground and get on with the business of constructing its home for the next 17 years.
Though the nymph remains in one place for years at a time, it will bestir itself to find another food source when the root it has been feeding on is tapped out. As the 17th spring draws near, the nymph, acting on some internal or external signal that remains a mystery, begins to burrow upward. So strong is its determination to embark on its new life that it will scrabble through pavement to get to the earth’s surface.
Strong as it is, the nymph can be destroyed by “progress,” in particular rampant suburban spread. Turning over the soil to create an ostentatious expanse of lawn can wipe out millions of vulnerable nymphs. So Takoma Park is more likely than, say, Potomac to enjoy one of nature’s most interesting phenomena. Still, with cicadas, you never know what’s going to happen until it happens.
One other thing: Cicadas are just the right size for popping into your mouth. With a flavor that has been compared to a cross between a potato and an avocado, they would seem to be the perfect snack food. Native Americans were quite fond of the crispy critters, though the settlers could never be persuaded to munch along, and few people today appreciate this rare taste treat. Cicadas are easily prepared: just dip in batter, and fry in butter until golden brown. Serve with cocktail sauce.