CICADAS
(Homoptera: Cicadidae)

Adult cicada © 2000 Audra Stechyshyn

There are several species of cicadas in Ontario. All are large in size (2-5 cm long) robust and somewhat triangular in shape. Their antennae are very short, and some are black and green in colour. The wings are held over the back in a sloping fashion and are membranous. Cicadas are very attractive and different in form from most other insects, and often attract interest when they are found.

The common species in Ontario are referred to as the dog-day harvest flies. They have a life cycle of four years or more. The 17-year locust (cicada) is more common farther south in the United States. This species may take 13 to 17 years to complete a life cycle.

Cicadas are well known for their high-pitched, shrill call. The sound is produced by the male, which has powerful muscles attached to the side of membranes that can be vibrated very rapidly. This droning sound is produced on hot, humid days in July and August.

Eggs are laid in the twigs and small branches of trees. The female deposits 10 to 20 eggs in each puncture beneath the bark. Upon hatching, the nymphs drop to the ground and enter the soil. They form a small cell in the soil near a tree rootlet from which they suck the sap. Nymphs develop very slowly taking 4 years or more. When the nymphs are full grown, they crawl out of the soil and up the tree trunk to a place where they grasp the bark firmly. The skin splits down the middle of the back and the adult gradually works its way out. They remain near the old cast skin until the body and wings harden and they are ready to fly.

It is not likely there will be enough cicadas in Ontario to cause important tree and shrub damage. Damage caused by the cicada egg laying may result in dieback symptoms of some tree branches. Prune out damaged branches if necessary.

H.W. Goble

PDCF-098 (Revised 2003/11/07)