Beat of the cricket

Crickets are the keepers of time. They keep the rhythm of the day and of the music of the wilderness.

The birds maintain the melodies, the bullfrogs the bass. The coyotes offer the dramatic rift in a song that might otherwise become monotonous.

But the crickets are like the drummers, ever present and consistent, giving all other musicians a steady beat to play against.

Crickets provide the background for the workings of nature. For people walking through the oaks or chaparral, the reliable hum and dependable pulsing of crickets renders chaotic thought into peaceful rhythm.

Most riotous during summer nights and fall evenings, crickets tell of darkening hours, shorter days and differing temperatures. They herald not only the time of year but also the time of day.

How hot is it?

The snowy tree cricket (Oecanthus fultoni), also known as the "thermometer" cricket, can tell us the temperature in degrees Fahrenheit. To determine this on the West Coast, count the number of chirps in 12 seconds and then add 38 to that number. The total gives the ambient temperature.

Although this species is rare in the Los Angeles Basin, the more common Riley's tree cricket (Oecanthus rileyi) chirps about twice as fast at the same temperature as the "thermometer" cricket.

Crickets are part of the order Orthoptera, which also includes grasshoppers, camel crickets and katydids. There are more than 300 species of this order in California. Most members are distinguished by their well-developed hind legs specialized for jumping or leaping. The femurs are enlarged to accommodate muscles which powerfully kick the tibiae downward and backward to propel the animal forward. These great leaps are used to avoid predators as well as for propulsion to become airborne.

Other common features in this order are heavy bodies, obvious antennae and mouth parts for chewing plants. Species in this order can be winged or wingless.

These insects are most notable for their musical talents. While pleasant and lending a certain atmosphere to summer nights, orthopterans chirp for the specific purpose of sexual encounters.

Sing a song

The males sing to attract females, much like a man will croon a serenade beneath his lover's window. Unlike the man, these insects use organs much different from the human larynx. They have specially modified ridges, knobs or pegs at the bases of their forewings or on their legs, which are rubbed together to make a sound. Nearby membranous areas then vibrate and amplify the sound. This process is called stridulation.

An alternate version of stridulation makes high-pitched creaking noises by rubbing roughened places on the hind legs against the forewings.

Another sound, called crepitation, is produced by rapidly closing and opening the fanlike hind wings. This results in a buzzing or cracking noise.

The last familiar sound is drumming, created when some part of the insect's body thumps against the substratum.

Good listeners

When an animal has welldeveloped sound mechanisms, they are usually accompanied by welldeveloped hearing devices.

Such is the case with orthopterans. The auditory organs of these insects are welldeveloped membranes connected to sensory nerves on the foreleg tibiae in crickets and katydids and on the abdomen in grasshoppers.

While these "ears" are able to hear most of the sounds in their environment, they are specially attuned to sounds generated by their own species.

Grasshoppers are differentiated from crickets and katydids by their short and relatively stout antennae, also by the different location of their auditory organs. To attract mates, grasshoppers will use stridulation as well as crepitation.

Katydids are large, green, leafmimicking insects with slender legs and very long antennae (often exceeding the length of the body). The male has a multitude of songs, while the female responds with a single click, indicating her position.

True crickets, in the family Gryllidae, are smaller than katydids and often black or brown, although tree crickets can be green. Only the males in this family bestow us with song.

A place in folklore

Unlike katydids or grasshoppers, crickets have made a name for themselves in folklore all around the world. In many places they are considered good luck and are kept as pets in Asia and some European countries.

If you find a gray one in a room it means money; a green brings hope and a black one illness.

In Brazil they mark the coming of rain. In Zambia a cricket is thought to bring good fortune to whoever sees it.

I find it interesting when an animal becomes a universal symbol for good luck. Can it really be coincidence? Or is it because many crickets eat plant pests such as aphids or scale insects, therefore lending to bounty?

Maybe it is the peace they bring by setting a tempo which we can all move to, bringing even the most antagonistic minds into rhythm.

Meghan Walla-Murphy can be reached at mwallamurphy @yahoo.com.