Now You See Them

Science calls them Lampyri-dae, but we call them fireflies, or lightning bugs. When they’re not around, which is most of the time, we don’t really miss them. Then, one May or June evening, our gaze will be broken by something we might have seen, then another, then we know. More than a source of amusement and nostalgia, the presence of these bioluminescent beings means something quite tangible. Their spasmodic flashes of greenish-yellow light assure us that summer is here. Less tangibly, the fairy-tale creatures seem the very essence of summer.

They are as elusive as summer itself, and as quick. Like the neighbors’ kids running through all the backyards well past bedtime, fireflies, which are nocturnal, don’t know boundaries and don’t play by the rules. With their photo-cytes, or light-producing cells, they manage to beat the sun at its own game.

If you want to catch one, you’ll have to be quick, and you’d better line your jar with something sweet because adult fireflies eat only pollen and nectar, if they choose to eat at all. They are hedonists with wings. (Should you come across a glow worm, take pity. Resembling a larva, she is a female firefly who has lost her wings.) If you do catch one, don’t be surprised if the jar looks empty. They are sneaky, quite able to control their rhythmic flashes of light.

And each firefly flash is a message, though not for us. The half-second of brightness is part of a signal system that brings the sexes together. And while it’s known that both the rate of flashing and the amount of time between a female’s response to the male are important, science can’t explain why certain fireflies choose to pair as they do.