Monday, May 21, 2007

Run-up to the Cicadas

Every summer, my neighborhood fills with the sound of cicadas.

Annual cicadas, I’d assumed, although now I know that few, if any, species of cicadas undergo an annual metamorphosis from egg to nymph to egg-laying adult. Instead, almost all species are periodic, having life cycles that range from 2-8 years -- most of it spent underground in the nymph stage. Only because each year brings the emergence of a combination of various species, do we hear the "annual" buzz that heralds the dog days of summer. It’s like working with fractions and lowest common denominators to predict which might be the jackpot year -- when the 2- and 3- and 4- and 5- and 6- and 7- and 8-year cicadas will all happen to emerge in the same summer.

I hope it’s not this year, because we’re just days away from the huge, synchronized emergence of a species with an ultra-long life cycle: the 17-year cicadas. I’m not surprised. I knew they were coming. I remember them from 17 years ago.

We’d bought our 80-year-old house in the fall of 1989, in an established suburb full of huge elms and maples. We happily spilled out into our yard the following spring and heard about the impending arrival of the periodic cicadas. We scoffed at neighbors who told us we wouldn't be able to hold a conversation outside amid the droning. I remember it eventually being true.

Cicadas aren’t dangerous, they’re not damaging. They’re just annoying: seriously clumsy fliers that bump straight into you instead of swerving; litterers whose shed exoskeletons form a crunchy carpet on sidewalks and patios. With estimates as high as 1.5 million cicadas per acre, that’s a lot of bumping and crunching.

Scientists predict the cicadas will return this week. I hear some have already been spotted in other suburbs. All I’ve seen so far are the signs: shed earthen casings (exit tunnels?) and emergence holes that can make a patch of bare ground look like it’s been brought to a boil overnight.

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