This summer marks the return of a special species of cicada

In just a few months, some of you will begin to hear a roar coming from the trees. A certain species of cicadas will return for a once-in-a -17-year appearance.

2021 is an appointment year for Brood X cicadas, an insect we have not seen, or heard, since 2004. X for the Roman numeral ten, they emerge after 17 years underground.

According to entomologist Frank Hale, “These are called periodical cicadas. They’re the longest living insects out there.”

Hale anticipates Brood X’ers in some middle and west Tennessee counties, but the majority of the emergence will be in the eastern end of the state.

Cicadas are harmless to humans, animals, crops, and most plants, and they serve a role in our ecosystem, but mostly what they do is roar, in numbers too big to ignore.

“I think it’s probably, could be as high as in the billions,” Hale states. “Definitely hundreds of millions of cicadas.”

When the cicadas emerge, it is dating season. Once a female is mated, she can lay up to 600 eggs.

Brood X males are literally flexing for females, creating noise by having their muscles rapidly pull on abdominal membranes called tymbals, causing them to vibrate loudly. All to serve their one purpose-- to make the next generation of cicadas.

“The noise is really loud. It’s the males, and they do have a chorus of these males, and they’re calling for the females,” he adds. “The females don’t do any of this, and the females are the ones that do the damage. They lay the eggs in the twigs. The males make all the racket.”

Cicadas make the noise to attract a mate and scare away birds, but humans get to hear this too. For some people, it is annoying, but others find this summer song kind of soothing.