Thursday, August 13, 2009

Summer serenaders

They’re out in force by mid-August, when the fireflies – our early-summer regulars -- have pretty much faded away. Now cicadas, crickets and katydids are singing their hearts out and rubbing their wings day and night. There’s no mistaking their great numbers or the urgency in their sounds.

Maybe we’re lucky these vast armies of insects that sound from trees and bushes are the size they are. But even if they were much bigger, their concentration would be the same: mating and propagating for survival of the species – and they still wouldn’t “see” us.

Why not? because, as one scientist-admirer of the bugs put it: “They don’t have enough time to do what they have to get done. Just a few weeks to mature, to mate, to survive, to lay eggs. And then it’s over in a few weeks.”

For the record, cicadas are in action mostly during the day, while crickets and katydids serenade at night. (One easy way to remember this is that it happens in alphabetical order: cicadas come first, so daytime for them; crickets and katydids follow, so night’s their time. Further, katydids often start a few weeks after crickets, just as they follow them alphabetically.)

The males make all the noise. Females listen, make their choices and respond. Then it’s eggs, nymphs and next summer’s new cicadas, crickets and katydids.

Male cicadas have been compared to percussionists: thin membranes in their thoraxes vibrate and air sacs amplify that sound – sometimes for blocks.

In contrast, crickets and katydids are fiddlers, making their music with file and scrape mechanisms on their wings, in a process called stridulation. Cricket chirp repetitions are directly related to temperature: the hotter the faster; the cooler the slower.

There’s so much more about these three fascinating invertebrates, such as the variety of sounds produced among different groups of them and the “periodical” variety of cicada – unlike the “annuals,” they emerge only every 17 years. (Mark your calendar for 2020.)

For now, the best thing to do might be to enjoy the songs and root the noisy guys on so these great summer sounds will always be with us. The first serious frost ends their season – and our music.

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