Crickets have been hanging around since spring, but many people become aware of them only at this time of year. There are a couple of reasons for that.

This is mating season for crickets, and they become what the scientists call "gregarious." Instead of looking for food, they look for other crickets. The males sing out to attract females, and the females jump on over. The noise level rises, and sometimes a crowd gathers.

It also is beginning to get cold, especially at night. Crickets avoid the cold because it kills them. So they try to find a warm building to take shelter in, such as a house.

So Eric Day, manager of the insect identification lab at Virginia Tech, sometimes gets phone calls after an autumn cold snap, with somebody on the other end of the line complaining that the noise keeps them awake.

Day can tell them about his own up-close-and-personal experience with chirping crickets. When he was a graduate student at the University of Illinois a decade ago, he had an alarm clock that made a "beep-beep" wake-up call each morning.

It was just the right tone to set off the crickets that lived in his house. His wife named it "the entomologist's alarm clock." He still has the clock, though it no longer beeps each morning.

He can also tell them what's happening. Only the male crickets chirp. They do so by rubbing their front wings together, moving a sharp edge against a ridged surface in a way that's been compared to a bow across a violin. There are different songs for courtship, fighting or sounding an alarm. Courtship songs are the shortest and softest, because the female usually is close by.

The warmer the temperature, the faster they chirp. According to an Ohio State University fact sheet, crickets chirp from four times a second to more than 200 times a second.

If you listen to cricket calls at night, Day said, at first they seem to blend together in a combined sound. But listen carefully, and you may be able to distinguish different ones.

There are at least 30 species of crickets in the Washington area. The ones that might hop into a house are most likely house crickets, which are tan; field crickets, which are black; or camel crickets, which are tan, wingless, humpbacked creatures that make no noise.

"Generally, you can't tell how they get in," said Jackie Carson, a naturalist at the Watkins Nature Center in Prince George's County. "They find those little spaces to get in. You are talking tiny holes, and maybe some can get in when people go in and out."

They are not especially pestiferous around here, Day said. Despite reports elsewhere, they do not chew fabric. They eat plants, "but I've never had a report of defoliation of plants in a field. They seem to have a low enough population that they are not causing economic damage."

Occasionally, someone will claim that a cricket bit. Day said that likely is not so: "They have spines on their legs, so you may feel a sharp jab when you touch them, but it's not a bite."

Soon, they will be silent. After mating, the female lays her eggs on plant stems or the ground, pushing out hundreds of them with a long slender ovipositor. Then that's about it for the adults. Reproduction uses up their energy, and the first frost kills off any left. They become food for other insects or scavenging creatures.

They can be maintained for a while in a jar or other tall container with a top that has a few small air holes. Catch them with a cup and a plate. All they need, Day said, is a "sponge that you keep moist and a piece of dog or cat food. . . . You might be able to keep them alive for several months and extend their summer."

-- D'Vera Cohn