Cicadas are insects best known for their loud singing during the summer. Cicadas are found throughout the world in both temperate and tropical regions. There are 2,500 known species of cicada and each species has its own song.
Cicadas are commonly 1 to 2 inches (2.5-5 cm) long. They have wide, blunt heads with prominent eyes and short, bristly antennae. Cicadas have clear, brittle wings that they hold over their body. Cicadas are best known for their ability to produce sound. By vibrating a set of muscles against a pair of “drums” on their thorax, male cicadas create a loud, repetitious song.
Male cicadas sing in large groups to attract females. The song of many cicadas is extremely loud. Members of a cicada population typically hatch from their eggs at the same time. They become adults at the same time, and they commonly mate at the same time. That means thousands of male cicadas begin singing at the same time. The loud buzzing songs of cicadas can fill a summer day. Most cicadas do not sing at night.
Cicadas have an interesting life cycle. Most cicadas spend only five to six weeks of their life above ground as winged adults. For most of their lives, cicadas live underground in the dark root systems of trees and sod. Cicada nymphs–nymphs are young immature insects–are stout, brown, wingless insects that feed on roots. Nymphs molt or shed their skins several times before they become adults. When a cicada becomes an adult, it digs its way out of the ground, climbs a tree, and feeds for several weeks before it mates. Females lay eggs in tree branches. Two months later the eggs hatch and a new generation of nymphs drop to the ground and burrow back into the soil. Each new generation of cicadas is known as a brood; a brood is made up of thousands of cicadas.
There are two common types of cicadas: the dogday cicadas that have two- to four-year life cycles, and the periodical cicadas that have 13- to 17-year life cycles. Dogday cicadas are commonly larger than periodical cicadas. Periodical cicadas live underground for nearly all of their 13 to 17-year lives. Periodical cicadas are among the longest-lived insects in North America.
Cicadas belong to the order Hemiptera, insects with sucking mouthparts. Because hundreds of adult cicadas are seen feeding on tree sap at the same time, they are often mistaken for locusts, a type of short-horned grasshopper with a tendency to travel in swarms. Cicadas are not locusts; they are more closely related to spittlebugs and leafhoppers.