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Cicadas: Big Numbers This Season

Cicadas

by W.S. Cranshaw and B. Kondratieff* (7/13)

Quick Facts

  • Cicadas are large insects that develop on the roots of trees and shrubs. Most are long-lived and may take two to five years to become full grown.
  • Male cicadas "sing" to attract females. Many produce loud, shrill buzzing noises.
  • Cicadas do little if any injury while feeding on plants. Adults sometimes cause injury when they insert eggs into twigs, producing splintering wounds.

student demonstrating how to build trap

Cicadas are among the largest Colorado insects in the order Hemiptera, which includes other sap-sucking groups such as leafhoppers, aphids and spittlebugs. Twenty-six species occur in the state. The largest, the "dog-day cicadas," are stout-bodied insects over 2 inches long.

Although abundant, cicadas are far more often heard than seen. Males make a variety of sounds to attract females. Most commonly heard are loud, often shrill, buzzing, sometimes with several individual insects synchronizing their songs. Other cicadas make clicking noises.

Despite their large size, cicadas cause little injury. The immature stages (nymphs) develop slowly underground. They feed on roots but cause no detectable harm to the plants. The greatest injury occurs when large numbers of certain cicadas, such as the Putnam's cicada, insert eggs into stems of trees and shrubs. This egg laying injury can cause some twig dieback.

Cicadas are sometimes mistakenly called locusts, a term properly used to describe certain migratory grasshoppers. This error originated when early European settlers encountered large instances of periodical cicadas in the Northeast. As they had not previously seen cicada outbreaks, they likened them to the locusts described in the Bible.

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Noisy Cicadas May Help Prevent Erosion, USU Researchers Say

You've probably lain awake at night wondering why God created cicadas - those noisy insects that buzz like motorcycles on hot, summer days.

A couple of Utah State University researchers have one possible explanation.The critters play a quiet role in the formation of hardpan or "duripan" soils in the West.

In a study area in the Goose Creek drainage of Utah's northwest corner, soil scientists Al Southard and Tom Furst have identified a thick layer of fossil cicada burrows overlain and preserved by a later volcanic deposit. The exposed burrows look like little elongated bags.

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