Looming cicada emergence seen as buggiest in decades
2 broods, quiet for years, near spring invasion
Trillions of evolution’s bizarro wonders, red-eyed periodical cicadas that have pumps in their heads and jet-like muscles in their rears, are about to emerge in numbers not seen in decades and possibly centuries.
Crawling out from underground every 13 or 17 years, with a collective song as loud as jet engines, the periodical cicadas are nature’s kings of the calendar.
These black bugs with bulging eyes differ from their greener-tinged cousins that come out annually. They stay buried year after year, until they surface and take over a landscape, covering houses with shed exoskeletons and making the ground crunchy.
This spring, an unusual cicada double dose is about to invade a couple parts of the United States in what University of Connecticut cicada expert John Cooley called “cicada-geddon.” The last time these two broods came out together in 1803 Thomas Jefferson, who wrote about cicadas in his Garden Book but mistakenly called them locusts, was president.
“Periodic cicadas don’t do subtle,” Cooley said.
At times mistaken for voracious and unrelated locusts, periodical cicadas are more annoying rather than causing biblical economic damage. They can hurt young trees and some fruit crops, but it's not widespread and can be prevented.
The largest geographic brood in the nation — called Brood XIX and coming out every 13 years — is about to march through the Southeast, having already created countless boreholes in the red Georgia clay. It’s a sure sign of the coming cicada occupation. They emerge when the ground warms to 64 degrees (17.8 degrees Celsius), which is happening earlier than it used to because of climate change, entomologists said. The bugs are brown at first but darken as they mature.
Soon after the insects appear in large numbers in Georgia and the rest of the Southeast, cicada cousins that come out every 17 years will inundate Illinois. They are Brood XIII.
“You’ve got one very widely distributed brood in Brood XIX, but you have a very dense historically abundant brood in the Midwest, your Brood XIII,” said University of Maryland entomologist Mike Raupp.
“And when you put those two together . . . you would have more than anywhere else any other time,” University of Maryland entomologist Paula Shrewsbury said.
These hideaway cicadas are found only in the Eastern United States and a few tiny other places. There are 15 different broods that come out every few years, on 17- and 13-year cycles. These two broods may actually overlap — but probably not interbreed — in a small area near central Illinois, entomologists said.
The numbers that will come out this year — averaging around 1 million per acre over hundreds of millions of acres across 16 states — are mindboggling. Easily hundreds of trillions, maybe quadrillions, Cooley said.
Brood XIV stretches into Cape Cod.
The origin of some of the astronomical cicada numbers can likely be traced to evolution, Cooley and several other entomologists said. Fat, slow and tasty, periodical cicadas make ideal meals for birds, said Raupp, who eats them himself. “Birds everywhere will feast. Their bellies will be full and once again the cicadas will emerge triumphant,” Raupp said.
The cicadas can cause problems for young trees and nurseries when their mating and nesting weighs down and breaks branches, Shrewsbury said.
Periodical cicadas look for vegetation surrounding mature trees, where they can mate and lay eggs and then go underground to feast on the roots, said Mount St. Joseph University biologist Gene Kritsky.