We have all heard the Cicada, some of us perhaps not knowing what they were hearing. In New Brunswick they fill the late summer air with a steady hum or buzz. But the insects making this sound are rarely seen. That is because they are arboreal, tree-living. The males are singing from the tree tops.
Cicadas are deemed harmless unless they occur in large numbers. The adults are in trees often fruit trees where they can do damage to orchards. The adults live only a few days when they mate and the female lays her eggs in slits she makes in the bark of twigs. These eggs hatch into larvae which drop to the ground where they burrow deeply into the ground along the tree roots. They become nymphs and live for 2 to 5 years (depending on the species) feeding on juice sucked out of the tree roots. Each year many burrow to the surface and crawl up the tree trunk. There they metamorphose into adults. The adults then mate, the females lay their eggs, the adults die and the cycle begins again.
There are two types of cicadas, annual and periodic. Here in the northeast we have only annual cicadas. Periodic cicadas occur in United States. Annual cicadas emerge annually to give us that high-pitched humming sound. Periodic cicadas live 13 to 17 years depending on the species. They all emerge at once producing 'cicada years' which has occurred in the northeastern US this summer. The annual cicadas live 2 to 5 years underground but their cycles overlap producing a population of adults every year. The periodic cicadas sometimes emerge in huge numbers which causes significant damage to trees.
Cicadas are classified in the family Cicadidae of the Order Hemiptera. They are widespread across southern Canada. The adults are large insects, 20 to 30 mm (1 to 2 inches) long. The sound is made by the males using sound-producing organs called tymbals located on the ventral side at the base of the abdomen. The tymbals are made up of a tight membrane stretched across an echo chamber. When this vibrates it produces the high-pitched incessant droning sound we associate with hot summer days.
The Canadian Cicada (Okanagana canadensis) is common across southern Canada and ranges northward to the edge of the boreal forest. It is black and reddish brown and its forewings expand to 60 mm. Although it is not often seen, it is common. Because it is such a large insect many people are afraid of them. Well, it is harmless except for the damage it does to trees. Birds love to feed on them. We will never have an apocalyptic emergence of these insects because we do not have periodic cicadas here in New Brunswick. Their high-pitched drone is loved or hated by all except those with hearing loss in the high decibel range. For me, it makes me smile when I hear them first beginning their song on a summer morning. I know then that it is going to be a beautiful, warm New Brunswick day.
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