How Darkness Can Illuminate the Insect Apocalypse
It was much too warm for a Massachusetts mid-October evening, and the bugs were there to say so. A sonic blanket lay over the Alewife Brook Reservation, a 136-acre spread of wetland, forest, and meadow just outside Boston—the buzzsaw purr of cicadas and the katydids’ rhythmic zipper noise woven between the pure-tone chimes of crickets—making it sound like late summer. This sound has felt especially welcome lately, amid reports of dwindling global insect populations usually labeled an “insect apocalypse” in the news.
Despite the racket, I couldn’t see any insects until Avalon Owens, an entomology graduate student at Tufts who has what she calls “super-vision for tiny things,” bent down to point out a sleeping bumblebee, nestled on the underside of a shrub’s leaf. And then another, under another leaf, and then two more. I pointed out a mosquito that had landed on her forehead; she gently brushed it away with a forefinger.
Owens—bumblebee earrings hovering over the collar of a hunting camo fleece—tells me my difficulties in fully perceiving the insect world around me aren’t unique to me. I had come to talk with her about her theory that part of what scientists call a decline in insect population is not an actual decline; rather, over the past few decades, bugs have started to hide where entomologists aren’t looking. Her reasoning goes like this: Since humans have been artificially illuminating the night, they have noticed insects congregating around lights. First there were a few at campfires, then a flutter at gas lamps, then flocks at gas stations and streetlights. Entomologists took advantage: To find insects or count them, they turned on lights. People started using lights to attract insects more than three centuries ago and still today, researchers collect much of their insect population data with light traps at night.
“You put out a light and see what comes to it,” Owens said. “And if they stop coming to it, you’re like, ‘Oh, there’s no insects left.’”
But think about what happens to those bugs, drawn to candle flames or gas stations, or entomologists’ light traps, for that matter. They’re incinerated, or mashed against a headlight, or become a well-lit snack for predators. And even if they survive their encounter with the light, they’ve spent their night loitering instead of eating or finding a mate. Generations
