New American Century

In my midwestern town, you can't escape the cicadas. They fill the trees and synchronize their calls in a pulsing drone, and I'd find it deafening if I hadn't grown up with it. To me, it's the sound of summer.

In the mornings when we leave for school, my sons typically find a few lying motionless on our front porch, and they are, as you'd expect, both disgusted and fascinated; they crouch and stare, hands on knees, inching closer to see if the insects might move. Sometimes they do, suddenly and with indignant clatter, and the boys scatter in gleeful terror. Usually they don't. On the walk, we trade theories for why these strange bugs seem to seek out our stoop to die.

One night, long after the kids were asleep, I learned the answer. I heard small thumps against our front door, spaced a few seconds apart. Peering out the window, I saw that it was cicadas, flying at full speed into our door and front wall. Often they would ricochet and continue flying, but sometimes they'd fall to the ground, dead or at least dazed. These were the unlucky ones we found each morning.

Cicadas orient by light. They stay level by keeping their backs towards the light and they fly toward silhouettes to find landing sites. Our porch lights and white walls—multiple light sources close to the ground; a broad, illuminated surface—disorient them, and because they are heavy and awkward flyers, they cannot correct course. They crash.

I turned off the lights, and I thought about how hundreds of millions of years of evolution produced this flight system, one that served well enough to carry cicadas across the globe. A century and a half of electric light has not been nearly enough time to adjust, and so they follow their instincts into the wall.

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