What are cicadas, and why do periodical cicadas emerge so seldom?

Cicadas are insects in the order Homoptera, and they are related to planthoppers and aphids. They have piercing-sucking mouthparts, which they use to pierce plants and suck out the plant juices. Immature cicadas live underground for years, where they feed on plant roots. Adults live aboveground, typically for about a month, where they mate and lay eggs.

There are two main types of cicadas, dog-day cicadas and periodical cicadas. The dog-day cicadas live underground for varying numbers of years, but some adults emerge each year.  Mass emergences of periodical cicadas in odd-numbered years are apparently a means to avoid being eaten by predators such as birds, thus assuring survival of the cicada species.

Related Content

Filter Total Items: 3

What sounds do cicadas make?

Cicadas make a variety of sounds, including very loud buzzing sounds. The males have tymbal organs that include rib-like bands on a membrane that can be vibrated very rapidly by a special muscle. The sounds include courtship calls  and squawking sounds when the cicada is handled or disturbed.

Read Full Answer

Where will the periodical cicadas emerge next?

The broods (hatchlings produced at the same time) of periodical cicadas (species in the genus Magicicada), and the locations and years of adult emergence, are well documented on the University of Michigan’s Periodical Cicadas

...Read Full Answer

Are cicadas harmful?

Cicadas are not harmful to humans and they rarely cause significant plant damage. However, the eggs are laid in slits in twigs, so during large emergences of periodical cicadas they can cause substantial damage to branches of trees and shrubs.

Read Full Answer
Filter Total Items: 5
Close-up view of a brown, empty shell that looks exactly like a live cicada, complete with antennae and individual hairs
July 15, 2014

USGS Bee Inventory and Monitoring Lab.Roooooarrrrrr!, Danger, creature from the black lagoon. Or...not. Here we have a close up look at the many interesting features that are left behind when a cicada emerges. This one was in my backyard and left his/her full body suit behind on the shed. Insects are just weird sometimes, how do they go from something that looks like a land crab to a zippy green flying bombardier?

USGS
July 21, 2009

Listen to hear the answer.

Image: Cicada (Magicicada sp.)
April 29, 2004

Cicada on a wooden post. Cicadas (Cicadidae, Magicicada) are 13- and 17- year periodical cicadas of North America. These insects display a unique combination of long life cycles, periodicity, and mass emergences. Often called "locusts," but they are not locusts; locusts are "grasshopper-like" and belong to the order Orthoptera.

Image: Cicada (Magicicada sp.)
April 29, 2004

Cicada exoskeleton and live cicada atop leaves. Cicadas (Cicadidae, Magicicada) are 13- and 17- year periodical cicadas of North America. These insects display a unique combination of long life cycles, periodicity, and mass emergences. Often called "locusts," but they are not locusts; locusts are "grasshopper-like" and belong to the order Orthoptera.

Image: Cicada (Magicicada sp.)
April 29, 2004

Cicada exoskeletons on forest floor. Cicadas (Cicadidae, Magicicada) are 13- and 17- year periodical cicadas of North America. These insects display a unique combination of long life cycles, periodicity, and mass emergences. Often called "locusts," but they are not locusts; locusts are "grasshopper-like" and belong to the order Orthoptera.