Physical characteristics: The seventeen-year cicada (sih-KE-duh) has a plump body, dull dark brown to shiny black in color, with reddish eyes, legs, and wing veins. They measure 1.37 to 1.57 inches (35 to 40 millimeters) in length. The underside of the abdomen has broad orange bands. The antennae are very short and hairlike. Legs are short and adapted for walking. At rest, the clear wings are folded rooflike and extend beyond the abdomen. The underground larvae are nearly colorless.
Geographic range: They are found in the eastern United States, east of the Great Plains.
Habitat: They live in a canopy of deciduous trees in temperate forests and rainforests.
The appearance of thousands of cicadas every seventeen years has fascinated naturalists and scientists for more than three hundred years. (Arthur V. Evans. Reproduced by permission)
Diet: Cicadas suck plant sap. Adults feed from twigs, while larvae attack roots.
Behavior and reproduction: Adults are active during the day from late May through early July. Males chirp loudly to attract both males and females. Larvae feed underground, feeding on the same root for long periods of time. As they grow larger they move to thicker and thicker roots. When they are ready to become adults, they dig a tunnel upward. They emerge from the soil and crawl up a tree or fence to molt for the last time. Each population reaches adulthood about the same time, every seventeen years. However, different populations called broods will reach maturity on a different cycle.
Males call to attract females. Mating occurs on stems with the male and female connected by the tips of their abdomens. Females embed their eggs in plant stems. The larvae hatch, drop to the ground, and search for a suitably sized root to feed. The larvae resemble the adults but lack wings, have strong front legs adapted for digging, and are incapable of reproducing. They molt, or shed their exoskeletons, five times over a seventeen-year period to reach adulthood. The adults live four to six weeks.
Seventeen-year cicada and people: The appearance of thousands of cicadas every seventeen years has fascinated naturalists and scientists for more than three hundred years. If abundant in nurseries and orchards, larval feeding can be harmful to trees. Adult females in large numbers can also damage twigs by the egg-laying activities. The sound of thousands of male cicadas singing at once is annoying to many people.
Conservation status: This species is listed by the World Conservation Union (IUCN) as Near Threatened, or likely to qualify for a threatened category in the near future. They are not under immediate threat of extinction, but many populations are threatened by the removal of large numbers of trees from their habitats. ■
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