Tuesday, April 26, 2016

Invasion of the Cicadas

Coming late May
by John Pogacnik, Biologist
Periodical cirada
Lake County is due for an invasion this summer and the invaders are a large black and orange insect known as the periodical cicada. the last time they occurred en masse in Lake County was 1999 and 1982 before that. Periodical cicadas spend the first 16 years of their life underground and emerge the 17th year. They will emerge in huge numbers toward the end of May when the soil is 64 degrees.

Cicada nymph
Cicadas belong to the insect family known as true bugs, which are plant-sucking insects. There are two groups of cicadas, annual cicadas and periodical cicadas. There are 13 specials of annual cicadas (most of which are green and black in color) in Ohio, but most are only found in the southern part of the state. Periodical cicadas are orange and black with red eyes and groups are called broods. In Ohio, there are four broods of 17-year cicadas. Brood V covers the eastern half of Ohio, southwest Pennsylvania and West Virginia. This is the only one affecting Lake County. Other broods affecting Ohio are brood Vii in extreme eastern Ohio, brood X in western Ohio, and brood XIV in southern Ohio.

Dog Day/Annual Cicada
The periodical cicadas will emerge in late May. If you get out at night, you may see the nymphs crawling up the trunks of trees. They climb up into the tree where they’ll shed their outer skin and emerge as adults. When adults emerge they are white, but then will darken into their black and orange coloration within a few hours. When their wings harden enough they will fly higher into the tree and by morning only the empty shell will remain. In a week or so the males will begin to call. They are often in such high numbers that their sound will drown out even the sounds of singing birds. They will mate, and the female will cut a slit into the branches of trees to lay her eggs. The egg laying will occasionally kill the ends of branches—called flagging—which is recognizable by the dead branch tips and occasional broken branches hanging. Later in the summer, the eggs will hatch and the young will climb down the tree where they will spend the next 16 years of their lives in the ground. The adults will typically be gone by the first week of July. 

Cicadas do not bite and are harmless to humans and pets. In Lake County, periodical cicadas will be most common in the southern half of the county. Their numbers have declined due to habitat destruction, so they may not appear in all areas. If you miss them this year, you’ll have to wait another 17 years.

To learn more, visit cicadamania.com.

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