CICADA NOISE EASING

Here today, gone tomorrow!

That buzzing or droning noise you've heard the past few weeks is beginning to subside.

A few more weeks -- maybe even days -- and the "periodical" cicadas will be gone for another 13 to 17 years as the new hatch hibernates underground, awaiting its coming out party sometime in the next century, 2011 to 2016.

As the singing subsides, visible reminders of the periodical cicada's spectacular emergence are evident in forests, parks and front yards.

Susan Burks, forest pathologist with the Missouri Department of Conservation, Jefferson City, said a number of calls of "flagging" were being received.

"Flagging" is the result of periodical cicadas' egg-laying. Female cicadas are slicing into the bark of live, pencil-sized twigs where they deposit eggs. When the eggs hatch, this often causes the tip of the twig to droop and turn brown, or "flag."

The damage, says Burks, looks ugly and may cost trees a year's growth, but healthy trees usually recover from the injury.

The sounds being heard today may be different from those cicada sounds of yesteryear.

The male periodical cicada, an ugly little insect, an inch or two long, black with red eyes and veins in their wings, has its own little love song to attract female cicadas, and each species has its own sound.

The big difference this year?

The 1998 periodical cicadas are sort of a phenomenon. This year's convergence is particularly unusual because it involves "two" very large broods -- 13-year and 17-year cicada broods, an occurrence that happens once every 221 years, and when the two groups start with their buzzing, they are a bit off key.

Cicadas covered the state, except Cape Girardeau.

"That's difficult to explain," said Joe Garvey, of the Missouri Department of Conservation district headquarters here. "We haven't heard any cicadas in the immediate area, although we have a number of wooded areas here and there."

The cicadas look for wooded areas. The female cicada lays her eggs in the twigs of trees and shrubs, placing them in small holes she made with a saw-like organ near the tip of her abdomen.

When the eggs hatch a few weeks later, the young nymphs fall to the ground, enter the soil and feed on roots. They remain in the ground 13 to 17 years. As an adult then, they emerge from the ground, shed their skin and live only long enough to breed, lay eggs and produce offspring.

The adults live only a few days, or weeks at the most.

"They have already started disappearing," said Garvey. The periodicals will probably be gone by the end of June or early July.

Then, it's "dog-day" cicada time.

The dog-day, or annual cicadas, appear throughout the Eastern United States, including Missouri, Illinois and Kentucky, in July and August. This brood of cicada is larger than the periodical cicadas.

Even the dog-day cicadas take from four to seven years to develop from an egg into adulthood, but some are seen each year, because different broods of young develop at different times.

"We'll probably see some of the dog-day cicadas in Cape Girardeau," said Garvey.

Missouri is home to several cicada species, including the dog-day broods.

The 13- and 17-year cicadas started emerging in mid-May.

The periodical cicadas are usually louder than the annual cicadas, said Garvey.

The cicada really doesn't have a voice. Instead, they owe their "voices" to paired elastic membranes behind their last pair of legs. When a "chorus" of cicadas sings in unison, it produces a noise loud enough to drown out lawn mowers.

Periodical cicadas are divided into seven "broods," or groups of individuals whose life cycles are synchronized.

Different broods are on different schedules, but their cycles are so reliable that entomologists can predict each brood's periodic emergences far into the future. It is easy to identify years when more than one brood will emerge.

This year is such an occasion.