Cicadas — the small but loud insects which cyclically emerge from their underground habitats — are due back in large numbers in central North Carolina with the arrival of sustained …
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PITTSBORO — Cicadas — the small but loud insects which cyclically emerge from their underground habitats — are due back in large numbers in central North Carolina with the arrival of sustained warmer weather and warm soil temperatures.
Along with Virginia and West Virginia, parts of North Carolina — including Chatham County — are expected to again experience the loud chirping of millions of cicadas in the coming weeks.
In some areas, said Chatham County Agriculture Extension Agent Debbie Roos, “some of them have already emerged.”
“Yes, we are expecting the emergence of Brood IX at any time in North Carolina,” she said.
There are approximately 150 species of cicada in the U.S., but “only the seven Magicicada species have synchronized development and periodical emergences (meaning that all individuals in a population are always the same age),” according to magicicada.org, which tracks the periodic varieties. “The rest of the species (the so-called annual cicadas) have unsynchronized development, so some individuals mature in every year and we hear them every summer.”
Unlike annual cicadas, periodical cicadas emerge every 13 or 17 years, depending on the species.
Brood IX, as the group making its presence known this year as they emerge from their underground habitats to mate, were last seen in 2003.
A separate group — known as Brood II — returned to parts of the eastern U.S. in 2013.
Roos said she first observed the reemergence of Brood IX earlier this spring.
“Back in late April I saw dozens of them in my pollinator garden,” she said, referring to the garden she created and maintains at Chatham Mills, 480 Hillsboro St., featuring mostly native North Carolina perennials, trees, shrubs, vines and grasses. “With the warm spell we were having at the time, following a warm winter, some of them emerged early because the soil warmed up.”
The insects emerge on a staggered schedule during the spring, said Roos, adding they “typically stick around four to six weeks.”
Beyond the loud noise they are prone to make — a mating call which the insects produce by flexing an internal muscle — and which is intensified by the large numbers of cicadas which emerge, the insect isn’t too worrisome for people. (Though the eggs they lay within branches can cause damage to a tree.)
In 2011, the last time North Carolina experienced a periodic (13-year) cicada invasion, Roos said the pollinator garden was hit.
“I lost a few young trees I had planted in my pollinator garden to cicada damage,” she said. “I had planted the native possumhaw trees in the preceding fall, and the branches were small enough (about pencil-size in diameter) to provide a perfect egg-laying site for the cicadas. The cicadas cut slits in the branches and insert eggs and this often causes the entire branch to die.”
Cicadas feed only on woody perennials, sparing vegetable and/or strawberry crops, Roos said.
Cicadas, however, aren’t a great threat to mature trees, though they “may cause the tips of smaller branches to die back,” she said.
“In general, gardeners don’t need to be concerned about cicadas unless they have very young trees,” Roos said. “Nurseries with trees and shrubs at the appropriate stage will sometimes use protective netting to exclude cicadas and prevent egg-laying.”
So cicadas aren’t a menace — neither toxic nor poisonous, they don’t bite or sting defensively — and their periodic presence is beneficial to the ecosystem.
“Many species of wildlife — including birds, mammals, reptiles, amphibians, and insects — eat cicadas,” Roos said. “Cicada nymphs spend many years underground and their tunneling aerates the soil and they are also part of the soil food web. And when the cicadas die their bodies decompose and provide nutrients to feed plant life.”
Randall Rigsbee can be reached at email@example.com.