17-year buzz: return of the cicadas.
Driving along on that muggy day in June 1987, I felt like I was in a science fiction movie. Even with the windows rolled up, the noise was unnerving: a steady, high-pitched "Eeeeeeee ..." sound which alternately grew louder and fainter as we drove past woodlands and open farm fields. I was experiencing the invasion of the 17-year cicadas; the large insects with striking red eyes and orange wing veins. This was the year of their emergence, and their sound was almost deafening. Even at 55 mph, it was like listening to a huge musical instrument whose volume was modulated by the distance to nearby trees.
The cicadas' loud mating calls make us pay attention to these remarkable insects. North American natives, 17-year cicadas are our longest-lived insects and occur nowhere else in the world. Though sometimes mistakenly called locusts, cicadas are actually related to plant-sucking aphids and leaf hoppers.
Cicadas come in two types: annual and periodic. Periodic cicadas are either a 13-year or a 17-year variety; each variety has several different species that are distinct in size, color and song. The 17-year cicadas occur primarily in the northern U.S.; 13-year cicadas are generally found in the south and midwest. Each species has several broods, and each brood has a different emergence schedule and range. While Brood X cicadas (with orange eyes shown above) range only as far north as Long Island, annual cicadas can be found in smaller numbers throughout New York State every summer.
The sheer magnitude of the periodic cicadas' emergence makes a lasting impression. After feeding more or less benignly for 17 years on shallow tree roots, all the nymphs in a brood burrow upward in late spring. At some predetermined signal, nymphs emerge through half-inch diameter holes and climb up tree trunks and other vertical surfaces. It takes about an hour for adults to exit the nymphal skin. In a short time, the soft, white adult hardens and darkens. Though rather clumsy fliers, the adults manage to array themselves throughout the tree canopy where the males begin their loud chorus in hopes of attracting mates.
Adult cicadas live for three or four weeks above ground and the mute females are ready to mate 10 days after emergence. Each female lays 400-600 eggs in slits they make in branches and twigs of nearly 80 preferred species of trees and shrubs. Eggs hatch in six weeks and the white, ant-like nymphs drop to the ground and burrow into the soil to begin the cycle again.
Periodic cicadas can damage small trees and shrubs by feeding on roots or laying eggs in twigs. However, most damage is minor and plants quickly recover. Harmless to humans, cicadas do not bite or sting, but can be a temporary nuisance as they buzz about.
Should you be lucky enough to witness a mass emergence of periodic cicadas, pause to enjoy the show. In addition to the constant din of males singing to attract mates in this great mating and egg-laying marathon, you may also observe the avian feeding frenzy that accompanies such emergences as birds take advantage of an easy and delicious meal. Remember--it'll be another 17 years before you have a chance to witness it again!
Retired environmental educator Frank Knight is a frequent contributor to the Conservationist.
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|Publication:||New York State Conservationist|
|Date:||Aug 1, 2004|
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