Periodical Cicadas

Life Cycles & Behavior

Immature periodical cicadas (nymphs) develop underground and suck juices from plant roots. After 13 or 17 years below ground, mature nymphs emerge from the soil at night into the morning hours and climb onto nearby vegetation or any vertical surface. They then molt into winged adults. Their shed outer skins or exoskeletons are found attached to tree trunks and twigs. The emergence is often tightly synchronized, with most nymphs appearing within a few nights.

Adult cicadas live for only two to four weeks. During this short time, they feed relatively little. Male cicadas sing by vibrating membranes on the underside of the first abdominal segment. Male courtship songs attract females for mating. Females are silent. Each species of periodical cicada has a distinctive song, and two to three of the species are common within each brood emergence. Click here to hear periodical cicadas singing together.

After mating, females lay their eggs in twigs ¼ to ½ inch in diameter. The female's ovipositor slices into the wood and deposits the eggs. One to several dozen eggs can be laid in one branch, with up to 400 eggs being laid by each female in 40 to 50 sites.

Cicada eggs remain in the twigs for six to ten weeks before hatching. The newly hatched, ant-like nymphs fall to the ground where they burrow six to 18 inches underground to feed.

During the spring of the emergence year, periodical cicada nymphs may build mud tubes that project three to five inches above the soil, apparently to escape wet or saturated soils. These tubes are often mistaken for the tubes that crayfish build.

Annual cicadas usually emerge from June through August. Their emergence is scattered over this time and they rarely emerge in noticeable numbers. Annual cicada males also sing to attract females. The cicada killer wasp often captures these insects to provision its nest in the ground.

Periodical cicada nymphs crawl up tree trunks and other surfaces at night to find places to molt into adults.

If you go out at night when cicada nymphs are emerging, you should be able to find the teneral (newly molted) adults which first appear creamy-white before acquiring their final color.

Periodical cicada nymphs often construct openings and mud tubes in areas where they will eventually emerge. This is most commonly seen in wet conditions.

Hundreds of nymphal exoskeletons can be found on tree trunks, branches and leaves after periodical cicadas have emerged.

Female cicadas locate males through the male songs. Female cicadas do not produce a song.

Female cicadas use their needle-shaped ovipositor to cut slits into small branches. They insert their eggs into these slits.

A month or two after the cicada adults have laid their eggs, many of the tree branches in which the eggs were inserted die. This is called "flagging" and it can look like considerable damage has been done. Fortunately, this damage is only dangerous to small trees and shrubs. Mature trees rarely suffer long term damage.

Damage to branch from periodical cicada egg laying. If the bark continues to peel back, the branch will be girdled.