LOUISVILLE, Ky. —
Billions of cicadas will emerge this year, with experts forecasting a rare "double brood" event in parts of the Midwest and Southeast United States.
“This is a situation where two separate groups, or broods, of cicadas will be emerging in the same calendar year," said Dr. Johnathan Larson, an entomologist at the University of Kentucky. "It isn't necessarily unheard of for this to occur."
This year’s expected broods, which are designated with Roman numerals, are Brood XIII (13) and Brood XIX (19).
Brood XIII emerges every 17 years, while Brood XIX emerges every 13 years.
This will actually be a historic emergence of these two specific broods. Larson said these two broods haven't emerged together since Thomas Jefferson was President of the U.S. in the early 1800s.
“It is also interesting because the two broods are fairly large, meaning there will be cicadas across a wide swath of eastern America,” Larson said.
How many cicadas will emerge in Kentucky, Indiana?
There’s good news for those living in Kentucky and Indiana: neither state is expected to see a large emergence of either of these broods.
According to scientists at UConn, Brood XIX is expected to arise in western Kentucky, but in small numbers compared to states such as Alabama, Georgia, and the Carolinas.
Illinois is the unlucky spot in the U.S. as both broods are expected to emerge within the state at the same time, but the overlap between the two will still only cover a select number of counties in the state.
And if you're worried about the billions of cicadas potentially cross-breeding and creating a type of “super-brood?” Larson said it's not likely.
“The crossover area for these cicada broods is limited in range to a few counties in Illinois. Ostensibly, they should not be able to interbreed as they shouldn't respond to the cicada calls made by cicadas not in their same species," Larson said. "There is evidence that crossbreeding can occur, but it probably won't be so widespread that we see a new brood born this year.”
Although we might see some cicadas across southern Indiana and Kentucky this summer, it’s unlikely we’ll see a mass emergence like the one of a few years ago.
Are cicadas harmful to my plants or pets?
Cicadas are largely harmless, especially to people and animals, but they can hurt some plants.
"Cicada egg laying can be detrimental to small newly transplanted trees in the landscape, as well as fruit trees," Larson said. "When the female lays her eggs, she creates a small slit in the twigs of trees and when there are many females on one tree, this can create 'flagging.' There will be small dead twigs hanging in trees. On large mature trees, this isn't an issue."
What's the best way to protect plants susceptible to cicadas? Larson recommends using cicada nets. Nets can be found online for generally $30 or less.
As for our pets, cicadas are actually edible and high in protein. Your pets, particularly dogs, eating a few of the crunchy bugs won't harm them, although Larson says pet owners shouldn't allow their animal companions to gorge on them due to possible soil contaminants potentially found on the bugs.
What's the difference between cicadas and locusts?
There's actually a big difference. Cicadas are cicadas, whereas locusts are actually a type of grasshopper. Early American settlers referred to them as locusts, however, because of how rare they appear.
"This is possibly because early colonists encountered an emergence and as this doesn't happen elsewhere in the world, the only reference they had for such large groups of insects were biblical locust swarms," Larson said.
As for another odd fact about cicadas, Larson said, "There is also a type of fungus that only infects periodical cicadas. It works sort of like an STI in them and causes their butt to fall off."
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