Cicadas to Appear
by James B. “Jim” Kea
Area Extension Forestry Agent – now retired
Thursday, February 9th, 2006
Parts of North Carolina are due this spring for a rare entomological occurrence — the appearance of a brood of cicadas that is seen only once every 17 years, according to a North Carolina State University entomologist.
The large winged insects should begin appearing in late May or early June in the northern foothills of North Carolina, primarily in Alamance, Forsyth, Guilford, Rockingham, Stokes, Surry and Yadkin counties, said Dr. Jim Baker, a North Carolina Cooperative Extension Service entomologist at N.C. State.
In some areas, it is likely cicadas will be present in extraordinarily large numbers. While these cicadas will be readily apparent to the casual observer — they may be found perched on trees and other vegetation — the presence of the insects may be most apparent in the “song” of the males, a shrill buzzing sound made to attract females.
“There will be some neighborhoods where the singing of the males will be absolutely deafening,” Baker said. “It should be really spectacular.”
Periodical cicadas, as cicadas whose adult stages are separated by a number of years are called, spend the time between adult appearances in the ground as nymphs, Baker explained. He added that people are already beginning to notice holes in the ground and mud “chimneys” up to 3 inches long from which nymphs will emerge.
Cicadas build holes and chimneys, which are known as turrets, several weeks before emerging from the ground. The holes and turrets are roughly three quarters of an inch in diameter. Nymphs build turrets when the ground is muddy.
Baker said there may be hundreds of holes or turrets in an area. Nymphs will begin crawling out of their holes and turrets in May and June.
After a nymph comes out of the ground, it crawls to the trunk of a tree or other object, where the insect clings until it molts into its adult stage. As they molt, cicadas leave behind skins called exuviae. Exuviae may be found attached to trees and other objects.
After mating, females produce eggs, which they insert into the bark of hardwood twigs. In six to seven weeks the eggs hatch and tiny antlike first-stage nymphs drop to the ground, where they burrow into the soil, where they’ll spend the next 17 years.
Adult cicadas, which are sometimes called locusts, are 1 to 1 1/2 inches long including the wings. The insect’s eyes, legs and the edges of the wings are orange. The remainder of the wing is clear.
Groups of periodical cicadas such as the ones that will appear this year are known as broods. The cicadas due to appear this year are Brood II. Baker said Brood II was first noticed and reported by entomologists in the late 1800s.
It is expected that Brood II will contain three different Cicada species. Males of the three species should sing at different times of day, Baker said, and discerning listeners should be able to tell a difference in the three songs.
Baker pointed out that periodical cicadas tend not to be adept at avoiding predators.
“They depend on sheer numbers to survive,” he said. Thousands of the insects may be gobbled up by birds and other animals, but there are so many of them that enough survive to reproduce and reappear 17 years later.
Because they appear so infrequently, the size of a periodical cicada brood can be reduced dramatically by human activity, Baker pointed out. Construction or other activity can destroy the nymphs while they’re in the ground. Some broods are thought to have been destroyed and become extinct in the interval between adult stages.
Baker said several other cicada broods are due to make North Carolina appearances in coming years. Two broods of 13-year cicadas (cicadas that appear in adult form every 13 years) are due over the next two years. Brood XVIII will emerge in Western North Carolina and the Sandhills area in 1997, while Brood XIX is due in the western half of the state in 1998. Another brood of 17-year cicadas, Brood VI, which should be particularly large, is scheduled to cover the southwestern two thirds of the state in the year 2000.
The adult stage of a cicada’s life lasts only about a month, so Brood II will probably have disappeared by mid July, not to return until 2013.
Dave Caldwell 4-23-96