SEPTEMBER
2008

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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09-11-08

Download the audio of On Six Legs: MP3, WMV.

Sound of Insect Music Ushers in Fall Season

Oscar Hammerstein probably wasn't thinking about insects when he wrote the lyrics for the title song of the Rodgers and Hammerstein musical, "The Sound of Music." But the words in the first two lines of that song, "The hills are alive with the sound of music/With songs they have sung for a thousand years," accurately describes the insect singing that ushers in the fall season.

As days get shorter and nights get longer, nature's insect chorus crescendos to fever pitch. From the top of the tallest trees to the soil surface, the earth is a cacophony of sound. At least during the evening and night hours when the insect songsters are in full fiddle.

So who are these six-legged troubadours? And what is the purpose of their serenade? First, only a few types of insects produce sound, and those that attract human attention are cicadas, grasshoppers, katydids and crickets. It is the males of these insects that sing. The purpose of the song is to attract the attention of the opposite sex -- although the song is sometimes used to mark territory.

Only adult insects can sing, and many species of singing insects go from egg to adult during one growing season. That means that in the early part of each season, most singing insects are immature and cannot produce sound. One exception to this is the periodical cicada. This insect spends 17 years underground and crawls from the soil in late May and early June and immediately sheds its last immature skin to begin life as an adult. And it immediately begins to sing, which it does incessantly from dawn to dusk.

Other species of cicadas emerge later in the season and join the regular host of insect singers. The emergence of the dog-day cicada occurs at such time that it has earned the reputation as a predictor for the first frost. According to an old saw, the first song of the cicada means six weeks 'til frost. The exact prediction is probably not accurate. However, consistent singing of the dog-day cicadas occurs at such a time that six weeks hence is a reasonable indicator of the first frost of the fall season.

Most insect singers appear to prefer to croon during the nighttime hours. Cicadas are the exception. Several species of cicada, including the periodical cicada, will sing during the hottest part of the day. Other cicada species, including the dog day, do most of their singing from dusk until sunset. Cicadas make the sound by vibrating a membrane found on their abdomen. They are the percussionists of the insect world.

Once the sun goes down, it is time for the insect fiddlers to rosin up the old bow. In the insect world, the bow might be a wing or a leg. Insect fiddlers make sounds by rubbing one body part on another, such as legs on legs, wings on wings or legs on wings.

Fiddlers include katydids that generally sing from trees, sometimes high up in the tree. In general, the sounds of katydids are harsh sounds, including one-syllable sounds like "tic, tic, tic" or two-syllable calls, including one that sounds somewhat like a harsh "katy-did, katy-did, katy-did," hence the common name.

Trees are also home to tree crickets. These insects make a soft trill – "eeeeeeeeeeeeeee" -- that seems to issue continuously from wooded areas. Tree crickets provide the background harmony for nature's insect symphony.

Lower to the ground in tall grasses are members of the group known as long-horned grasshoppers. The long horn, in this case, refers to the long antennae of the insects. These grasshoppers hang on stems of grass and produce continuous sounds like "zzzzzzet, zzzzzzet, zzzzzzet."

At ground level, the true crickets are singing their song. The most recognizable is that of the field cricket – "creek, creek, creek." Or a sound that is the inspiration for the name cricket – "cree kay, cree kay, cree kay!"

In the fall, woodlots and meadows of temperate regions are indeed alive with the sound of music. Music provided by a hearty band of insect musicians.

 

Writer: Tom Turpin
Editor: Olivia Maddox