The cicadas soon filling the north Georgia woods with “
The 17-year Magicicada is expected to appear in north Georgia
in late April or early May. Nymphs emerge when the soil
temperature inside the exit tunnel of the soil gets above 64
degrees Fahrenheit.
Adults emerge after 13 or 17 years underground
These cicadas are called “periodical” because they emerge only
as adults after years underground. They’re found in eastern
North America. The seven species of the genus Magicicada
include four with 13-year life cycles and three with 17-year
cycles.
This year’s “Brood X” population is the largest of the 17-year
broods. Cicadas are expected to emerge in parts of 15 states
from New York to Georgia to Illinois.
Generally, 17-year species are found in northern regions, while
13-year cicadas are mostly in the South and Midwest.
Wherever they emerge, you’ll know it.
They create “the song of summer”
“The
chorus is known as the song of summer,” said Nancy
Hinkle, an entomology professor with the University of Georgia
College of Agricultural and Environmental Sciences. “If you
grew up in the South, you know what they sound like.”
The males of this plant-sucking insect use acoustic signals or
songs to attract females for mating.
They sing with a loud buzzing that goes on all day long. With
populations that can reach up to 1.5 million cicadas per acre,
the sound can be deafening.
They make the noise by vibrating two shell-like drums along the
sides of the abdomen. Strong muscles vibrate the drum membranes
several times per second.
The resulting high-pitched, rapid clicks are resonated through
air sacs and other structures to control sound volume and
quality. The upward angles of the wings form a megaphone-like
chamber that further amplifies the sound.
Black bodies, red eyes and orange wings
Magicicada adults have black bodies. But they have striking red
eyes and orange wing veins, with a black “W” near the tips of
the forewings. Most emerge in May and June.
These insects are harmless to humans, Hinkle said. They’re not
poisonous. They aren’t known to transmit disease, either.
The only harm a Magicicada may cause is to the trees it feeds
on or lays eggs in. Laying eggs can damage the tree by breaking
twigs. Larger trees usually withstand their presence.
The long life cycle ends shortly after the cicadas appear as
adults.
After the females lay eggs in tree branches, the nymphs fall to
the ground. They spend their whole lives in the soil, sucking
plant roots for food.
After 17 years of developing, all the cicadas in an area emerge at the same time. “It’s amazing how they know to simultaneously
surface … every 17 years,” Hinkle said.
They live just four to six days
Newly emerged cicadas work their way into trees and spend four
to six days as immature adults before they harden completely.
They don’t begin adult behavior until this maturing period is
complete.
The adults live for only five to six weeks, Hinkle said. During
this time, they search for mates and lay eggs.
“These insects are considered good luck in the Chinese culture
because they signify long life and immortality,” Hinkle said.
