A once-in-a-lifetime cicada season is hatching in the U.S. this spring. Philly likely won’t hear the noise.

This spring arrives an ecological event that hasn’t occurred since the Louisiana Purchase: Two broods of cicadas emerging at the same time in the U.S.

Every year, cicadas — with their harmonious droning or headache-inducing cacophony (depending on whether you love or hate them) — emerge after completing almost the entirety of their lifecycle underground. This year, the 17-year-old Brood XIII and 13-year-old Brood XIX will poke their heads out in late April and early May, according to Michael Hutchinson, an entomology program manager for the Pennsylvania Department of Agriculture.

However, this once-in-a-lifetime cicada season, which hasn’t been seen since 1803, won’t be a “swarmageddon” for the Philly region.

“Brood XIII is going to be emerging out in the Midwest, and then there’s Brood XIX, which is in the more southern U.S. They will converge, and Illinois is going to be inundated with cicadas,” said Hutchinson. “But, as far as I know, Pennsylvania’s really not on the radar for either of these broods.”

Besides, we already have annual cicadas, he said.

In parts of Pennsylvania, New Jersey, and Delaware, there are annual cicadas known as “dog day cicadas,” that people hear every summer, said Hutchinson.

Then, there are periodical cicadas that operate in groups, or “broods,” living 13- or 17-year lifecycles across parts of the U.S. There are more than a dozen 13-year and 17-year cicada broods that all emerge at different times depending on species and location.

Here’s what you need to know about cicadas in the Philly region.

Cicadas are sap-sucking insects that belong to the same family as the spotted lanternfly and other plant-hopping bugs. They have a long piercing mouthpart, like a lanternfly, that slowly sucks the nutrients out of tree roots. They live the majority of their life underground.

The big difference is that the spotted lanternfly is an invasive species and can kill local plant life, while local trees and plants have evolved alongside cicadas, unharmed for thousands of years, according to the Pennsylvania Department of Conservation and Nature Resources.

Periodical cicadas are one to two inches long, with a black shell and red eyes, Hutchinson said, while dog day cicadas are a similar size but with greenish-black shells, wings, and eyes.

No. They belong to separate bug families. Cicadas are more closely related to other plant-sucking and plant-hopping bugs, while locusts are closer to grasshoppers, said Hutchinson.

In the Philadelphia region, periodical cicadas emerge in the spring during April and May. Hutchinson said dog day cicadas come out during the late summer months when it’s hot out in July and August, hence the name.

For both types of cicadas, their entire lifecycle can be nearly 20 years. Above ground? They live just a few weeks to a month, said Hutchinson.

Cicadas make that chirping sound through a structure on the side of their abdomen, or thorax, right behind their wings. It’s big enough that if you pick up a cicada, you should be able to see it, said Hutchinson.

“It kind of reminds me of a bendy straw, where you can contract and expand the bendy part and you get a weird sound,” Hutchinson said. “Picture that, but they can bend, contract, and expand that bendy straw dramatically faster than a human could, and you get this incredibly loud noise.”

In large enough numbers, cicadas can become deafening.

“They can get up to 100 decibels... The interesting thing about that is 85 decibels is what experts consider the threshold to wear ear protection,” said Hutchinson. “One hundred decibels is kind of like a gas-powered lawn mower or maybe a hair dryer on high setting.”

Cicadas are not harmful or dangerous. In fact, they’re a five-star, all-you-can-eat buffet for birds, rodents, and small animals when the cicadas emerge each year. This is a good thing for the ecosystem, said DCNR’s natural resource program specialist Ryan Reed.

“They are high in protein and other nutrients and highly prized by birds, possums, raccoons, and squirrels. During the prior hatch in 2004, I was lucky enough to harvest a huge spring gobbler amid the din of the cicadas. I opened its crop to see what the bird was consuming and found 14 cicadas! These insects can be a valuable boost for many forest dwellers.”

However, if you have newly planted trees, it’s not a bad idea to take action against cicadas, said Hutchinson, because cicadas make cuts into tree branches to plant their eggs, which can harm younger, weaker trees.

“If you have an orchard or a tree nursery, or you’re a homeowner that just transplanted a small tree into your yard, those trees are definitely in danger of having some damage and even death just because of the number of cuts that these insects are making on the branches,” he said.

Hutchinson recommends getting quarter-inch netting to wrap around vulnerable trees. Quarter-inch netting should work for cicadas as they’re fairly large bugs, he said.

No. Like the spotted lanternfly, cicadas can’t bite.

No. Cicadas aren’t toxic to your pets, according to Hutchinson. However, if you let the furry friends gorge on cicadas, that could lead to a stomach ache.

Expert sources

• Michael Hutchinson, entomology program manager, Pennsylvania Department of Agriculture
• Ryan Reed, natural resource program specialist, Pennsylvania Department of Conservation and Natural Resources