|
|
The Cicada
Nature Bulletin No. 273-A September 9, 1967
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F, Eisenbeis, Supt. of Conservation
THE CICADA
In the summer of 1956 we had a plague of Periodical Cicadas, or "17-
year locusts" in the Chicago region. There were countless millions of
them during June and early July, clattering through the air or crawling
on trees and bushes, Insect-eating birds and mammals got fat. The
"song" of just one male cicada sounds like a buzz saw going through a
log, and the metallic screeching of millions -- sometimes a continuous
clamor, sometimes rising and falling in waves -- made a nerve-wracking
din. People were frightened when those big insects, actually harmless
but fearsome in appearance, lit and crawled upon them. It was like a
bad dream. Then they disappeared but their progeny will return in 1973.
That was Brood XIV, so labeled by the U.S. Department of Agriculture.
There are many broods of the 17-year Periodical Cicada -- some very
numerous and widely distributed; others small and local -- which
emerge in different years. There are also several broods, mostly in the
south, which emerge every 13 years. One of these, a whopper, extends
as far north as Illinois.
They are not locusts. They are by far the largest members of a great
family of insects which have mouth parts for sucking the juices of
plants but not for biting and chewing. This includes the spittle bugs, leaf
hoppers, scale insects, and the aphids or plant lice.
The adult Periodical Cicada is about an inch long, with a stout
brownish-black body and a large head with prominent reddish-orange
eyes. The transparent wings, when held roof-like above the abdomen,
extend beyond it. They have reddish margins and veins, with a black
"W" near the end of each front wing.
The song of the male is produced by vibrating drum-like membranes
over a pair of sound chambers on the abdomen. The female, laying from
400 to 600 eggs has a dagger-like ovipositor with which she makes a
series of slits on the underside of tender twigs -- usually on an oak, a
wild crab, or an apple tree. In each slit she lays from 12 to 20 eggs. In 6
or 7 weeks these hatch into ant-like nymphs which drop to the ground
and burrow until each finds a tree rootlet -- anywhere from 1 to 10 feet
down. There it remains for 13 to 17 years, sucking juice, until full-
grown. Then it tunnels to the surface and emerges, usually at night,
crawls up on a tree or a weed stem and clings there. Presently, its skin
splits down the back and an adult appears. From 10, 000 to 40, 000 may
emerge from the ground beneath one large tree but usually there is no
noticeable damage from the feeding of the nymphs upon its rootlets, nor
from the sucking of sap from its twigs by the short-lived adults.
However, the twigs punctured to receive the eggs usually die, drop
off, and cause some injury.
There are many species of cicadas in North America. The common dog-
day cicada, or harvest fly, which we hear whirring continuously every
August, is much larger, has greenish margins on its wings, and is
believed to have a 2-year life cycle. After so long underground, no
wonder they celebrate.
To return to the Nature Bulletins Click Here! |
|
Update: June 2012
|
|
