Millions of cicadas will emerge in the eastern and midwestern United States in the spring and summer of 2024. Here is what you need to know about Charlotte's cicada population.
2024 is a notable year for cicadas, as the annual brood will co-emerge with Brood XIX, a periodical species that only emerges once every 13 years.
Scientists predict most of the periodical 13-year brood will emerge from mid-May to early June but are unable to pinpoint an exact day or week. However, the annual broods of cicadas will emerge from June to August.
In North Carolina, researchers predict that Mecklenburg County will be affected by the Brood XIX cicadas. Buncombe, Cabarrus, Chatham, Davidson, Davie, Gaston, Guilford, Montgomery, Randolph, Rowan, Stanly and Union counties will likely also be affected.
It can be difficult to estimate cicada emergence numbers due to the changing habitats, but Dr. Sarah Stellwagen, an entomologist with the Department of Biological Sciences at UNC Charlotte, gives rough estimates.
"[Charlotte] specifically is one of the [cities] where they're supposed to come out. There can be a million or a million and a half per acre," said Stellwagen.
Cicadas are insects characterized by their wide-set eyes, transparent front wings and loud songs.
Two types of cicadas will appear during this emergence: annual or dog-day cicadas and periodical cicadas. Annual cicadas are generally green with black eyes, while periodical cicadas are black with red eyes.
Can they hurt me?
Cicadas cannot hurt people or pets and are not dangerous to touch.
"They can't harm anyone. But of course, a lot of people have a visceral reaction to an alarming number of bugs that are coming out at one time," said Stellwagen.
If they land on a person, cicadas can be gently brushed off. If there is concern about cicadas being nearby, avoid using loud power tools; cicadas may mistake the droning noise for another cicada and gather around.
"I don't think it's going to impact anyone other than maybe crunching on them under their feet if they start falling off the trees when they die," said Stellwagen. "There are just going to be a lot of them, and the birds are going to be fat and happy, and we'll get to watch some interesting cicada behavior that most of us haven't seen for quite a while."
Why do they leave their shells everywhere?
Similar to crustaceans, cicadas molt as they age. When reaching adulthood, cicadas are limited by their smaller exoskeleton. As a result, they must molt their old exoskeleton, exposing their new body and wings.
"The fifth instar [is] the last molting stage before they actually come out. They will start crawling up, and they will molt similarly to how we've seen our dog-day cicadas leave their little casing on trees," said Stellwagen.
They will then hide in trees or other coverings to allow their exoskeletons to harden fully, as they are still vulnerable to predators.
What is that noise they make?
Using muscles in their bodies, male cicadas vibrate ridged areas in their thorax called tymbals. These tymbals are flexible and contracted, creating a quick noise when drawn together and released.
This movement can be repeated between 300 and 400 times per second, creating the droning noise heard during the summertime. The cicadas' hollow thorax amplifies the sound, which can reach levels of up to 100 decibels. Male cicadas use these 'songs' to attract females to mate.
"The males will congregate in trees together in giant choruses, calling to the females to try and attract them in to mate. They can get really, really loud because they all tend to kind of all come together," said Stellwagen.
Female cicadas can also create sounds, using their wings to create a clicking noise.
Cicadas sing during the hottest parts of the day and are unlikely to continue their song at night unless artificial light sources surround them.
Do they affect plants or crops?
For the most part, cicadas do not harm shrubs and trees. Newly emerged cicadas drink plant sap, but periodical cicadas have been shown to cause damage to young trees by laying eggs. Young woody plants should be covered with cheesecloth or some form of bird netting to prevent cicadas from laying their eggs.
