Periodical cicadas emerging after 17 years underground

LEXINGTON, Ky. (ABC 36 NEWS NOW) — These noisy neighbors are starting to make their way back up to the surface after 17 years underground.

Blake Newtown with University of Kentucky’s entomology department says people will begin to hear loud noises coming from periodical cicadas.

“It almost sounds like jet engines,” Newton said.

While the periodical cicada comes out every 17 years, the annual cicada appears every year.

“The difference is the periodical cicada’s, when they come out, they come out in huge numbers and they also tend to come out a little earlier in the year, like May and June,” Newton said. “The other big difference in them is their appearance.”

A periodical cicada is black with red eyes. An annual cicada is dark green.

“They’re not harmful in any way,” Newton said about periodical cicadas. “In fact, we wouldn’t be too surprised to hear about peoples’ dogs munching on a few of them.”

Newton said the only thing these cicadas pose a threat to is small trees.

“They lay their eggs in twigs, but a baby tree is essentially all twigs,” he said.

After they lay their eggs, these adult cicadas die. The newborns will then make their trek back to the soil.

“They will feed underground, right underneath us, for the next 17 years, and then they will come out again,” Newton said. “It’s very unusual, very few insects or any kind of animal does a life cycle like this, so it’s an interesting phenomenon that we only get to see like a couple of decades.”

While many theories exist as to why it takes 17 years for them to reappear, Newton says they believe it’s the insect’s strategy to protect them from predators.

“Predators like birds, and snakes and things that might like to eat cicadas, they don’t necessarily have a very long memory,” he said.

While those predators might forget, nobody is able to ignore these cicadas when they reemerge in thousands.