Discover the Remarkable Moths of the Night

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By Terry Krautwurst

It is late, very late — 2:30 a.m. or so — and I am out prowling my yard. The air is still and warm and moist, the sky a haze of swirling gray clouds easing eastward, alternately covering, then revealing, then covering again a few high twinkling stars and the dim sliver of a new moon.

Quiet. Walk like a fox. Though I’ve come for another purpose — I’m seeking a closer look at the night’s elusive moths — right now I’m playing red-light-green-light with crickets. How silently can I move, how many steps can I take before they hear me and stop their steady chirrr-chirruping? One step, two steps, three, four — the chirping stops: red light!

I freeze in my tracks until, several seconds later, the song resumes, and I try my stealth again. One step, two steps; this silly game actually is no small challenge. A cricket is a remarkably sharp-eared creature, with not just two but four sensitive hearing organs: a pair on each foreleg, just above what we humans might think of as a “knee.”

The organs, called tympana, are small round openings; across each is stretched a thin membrane that vibrates when struck by sound waves, much like our own eardrum. A cricket on alert will cock its body to one side and raise the opposite foreleg to get a better listen.esigned to detect the faint rustle of a predatory insect or the far-off calls of a willing mate, a cricket’s hearing is more than a match for the smash and crunch of a human sneaking around in the middle of the night.

Three steps, four, five — this time when the chirping stops and then resumes I stay where I am and, starting to count the chirrups, glance at my watch.rat, too dark to see. I’ve been counting cricket chirps since I was a child, when I first read that the number of chirps a cricket produces in a given amount of time can serve as a sort of thermometer. The formulas vary, but the idea’s always the same: Count the number of chirps in X seconds or minutes, then add, subtract or divide by Y, and you have the temperature.

In principle, at least, the notion makes sense. Crickets, like other insects, are cold-blooded (their body temperature matches the temperature of their surroundings) and are more active in warm weather. They chirp by raising their forewings at an angle and rubbing the bases together. The warmer the temperature, the faster they rub.

Never mind that different species of crickets chirp differently, at different rates. Over the years I’ve found the cricket thermometer to be right almost as often as it is wrong. Still, I go on counting, if for no other reason than I want to be able to tell the temperature from cricket chirps. I feed my faith on those occasions when the chirps and the thermometer actually come close to agreement. When they don’t — well, what do you expect of unscientific folklore, anyway? In my experience, the temperature-telling formula that’s closest to what you might call reliable is: