Across the Northeast, the seventeen-year cicadas are singing again. Fifty-one years ago—three generations of these insects ago—Princeton University gave Bob Dylan, by then already famous, an honorary degree at its commencement ceremony. When the event took place (outdoors, as was customary), the great-grandparents of today’s seventeen-year cicadas sang so loudly that the speakers could barely be heard. The high-tone Ivy League surroundings shook the twenty-nine-year-old singer; he later wrote, metaphorically, that the head of the man standing next to him was exploding. But the insects soothed him. He described the “locusts” as “singing for me,” in a song that appeared on his “New Morning” album, from 1970. The lyrics of “Day of the Locusts” say that he went to “the Black Hills of Dakota” immediately afterward and was “glad to get out of there alive.”
From a poetic standpoint, “locust” is a better word than “cicada.” The first sounds both scarier and tastier. As a kid, I thought that “locust” and “lotus” might be the same; I had heard about the lotus-eaters, known for their carefree lives. I assumed that locusts were very edible insects, perhaps even delicious. The Bible said it was O.K. to eat them. (Leviticus: “Even these . . . ye may eat; the locust after his kind, and the bald locust after his kind.”) The Biblical locusts also descended in vast numbers sometimes and ate all the crops in the fields and caused starvation. With the old-time locusts, evidently, it was life or death, eat or be eaten. Locusts still have a mythic and literary aura that the un-Biblical cicadas don’t. Actual locusts are large grasshoppers, and they and cicadas belong to different families.
After cicadas emerge from the burrows where they’ve been for however many years (the cycles are different, depending on the species), they climb onto trees, hatch from their nymphal casings, and take on winged form for mating. Cicadas are harmless; during their four to six weeks as winged insects, they eat sparingly, like humans afraid of having bad breath on a first date. The noise that they create is the males trying to attract females. Seventeen-year cicadas (and other periodical cicadas) aren’t all on the same cycles nationwide. Different regions have different broods. In Ohio, where I grew up, that region’s seventeen-year cicada brood emerged in massive numbers in June of 1965, when I was fourteen. Everybody called the insects locusts back then. I lived in the small town of Hudson, and the locusts/cicadas appeared during its annual House and Garden Tour, which was not an event of such long standing that it had often needed to take into account a once-in-every-seventeen-years insect swarm.
The number of insects came as a surprise. They got all over the streets of the town and crunched under the visitors’ tires and shoes. The sidewalks became slick with squashed bugs. I imagine that the tour hosts had to put extra doormats in their entryways, and maybe antique iron boot scrapers on their stoops. At fourteen, I did not need to deal with the details, and our family’s house was not on the tour. After cicadas mate, they die and fall to the ground and return their protein to the earth, whether it wants it or not. In death, many of the corpses are dry and sturdy, like trinkets. Along the bug-covered streets, kids set up card tables and tried to sell the dead bugs as souvenirs. Some kids strung pieces of thread through them to make them (we thought) into earrings. I don’t remember anybody buying them.
Seventeen times six is a hundred and two. Subtract that from 1965 and you get 1863. That year, the cicadas emerged in Ohio not long after news arrived of the North’s defeat at the Battle of Chancellorsville. At the time, my great-great-grandfather and other relatives were serving in the Fifty-fifth Ohio Volunteer Infantry, mustered in the town of Norwalk. Nothing as terrible as Chancellorsville had happened to Norwalk before. In the battle, the Fifty-fifth Ohio was on the far-right flank when tens of thousands of troops, led by General Stonewall Jackson, burst from the adjoining woods, having encircled the entire Union Army. Jackson’s bold maneuver sent the Yankees running for their lives, with yelling Rebels in close pursuit. Many Norwalk men fell, dead and wounded. (My relatives survived the rout, but never quite got over it.) Later, the Union forces regrouped, and the Battle of Gettysburg, two months after Chancellorsville, turned back the South’s advance. Ohio papers that printed the latest from the war during that decisive spring and summer also noted, sometimes in little items at the bottom of the page, the arrival of the “seventeen-year locusts.”
Another species of cicada emerges every thirteen years, rather than every seventeen. Biologists have speculated about why the insects’ life cycles are so long, and why the cycles are in prime-number years. One explanation, from Simon Singh, in “Fermat’s Enigma,” is that waiting for a prime number of years to hatch gave the insects an advantage over their parasites. To coincide with the seventeen-year cicadas, a parasite that emerged every year would have to wait sixteen years between cicada hatches; the only other cycle that would work would be for the parasite to emerge every seventeen years—in either case, a long time between meals. A parasite with a two-year life cycle would have to wait thirty-four years between one meeting with the cicadas and the next; a parasite with a three-year cycle would have to wait fifty-one years, and so on. Meanwhile, the cicadas were in the soil, living comfortably on sap from tree roots for seventeen or thirteen years. The evasive tactic seems to have worked. Today, no parasites associated with these cicadas have been found, which may mean that the presumed parasites went extinct, and that the long, prime-number life cycles successfully circumvented whatever foe the cicadas were trying to avoid. The life cycles continue even though the threat that produced them is gone.
A thousand cicada life cycles ago, there weren’t seventeen-year cicadas making their late-spring racket in what’s now the Northeast, because most of the region was under ice. The glaciers have been gone for about fourteen thousand years, and an environment similar to what exists today has existed for about nine thousand. From the native peoples to the Dutch to us, countless human generations have heard these insects. Peter Stuyvesant, the director-general of New Netherland, would have heard them in 1647, and they would have sung in 1732, the year that George Washington was born. Because of their longevity, which is extreme for insects, and their Brigadoon-like reëmergences, the cicadas seem to exist almost outside of time.
The loudness of the seventeen-year cicadas, when they are in the trees in massive numbers calling for mates, has been compared to the decibel levels reached by airplanes, chainsaws, motorcycles, and rock concerts. Humans who heard the insects’ deafening racket before any of those things existed did not know that they were listening to the future. It’s not just in loudness that the cicadas are unique. Their mating noise features a nerve-jarring, electric zzzzzzzzzz that’s similar to the sound of any one of a million modern-day electronics. People of former times would have been surprised if they’d known how much of the world to come would sound like cicadas. But, when we hear them now, we may be listening to the past. The insects emerge when soil temperatures reach sixty-four degrees. What happens when that temperature starts being reached every January? Or when the soil never goes below sixty-four degrees? Our part of the planet may be too hot for today’s cicadas’ fourth-great-grandchildren, who will be coming a hundred and two years from now, in 2123.
