by Tens of billions of noisy cicadas are set to emerge from the ground in the coming weeks in a rare synchronized event that took place 221 years ago.
The winged insects are expected to appear across the Midwest and Southeast beginning in early May, with the double emergence of two different broods of periodic cicadas. These bugs spend several years underground before coming to the surface to participate in regrettable mating rituals.
This year’s emergence is expected to be unusually large, with some experts estimating that more than a trillion cicadas could cover parts of the country where the two broods overlap.
Cicadas are harmless to humans, although the large numbers of insects and their loud mating song are a nuisance to some.
For bug enthusiasts, it’s a once-in-a-lifetime opportunity to experience two cicada broods emerging together, since the last time it happened was in 1803, when Thomas Jefferson was president.
“It’s something that no one alive today has seen and no one alive today will ever see again,” said Jim Louderman, a collection assistant in the insect department of the Field Museum in Chicago. “For entomologists, it’s a really big deal.”
Emerging this spring will be Brood XIII and Brood XIX cicadas. The former group lives on a 17-year cycle and is usually seen in the Midwest, mostly in Illinois, but also in parts of Iowa, Wisconsin and Indiana.
Brood XIX cicadas, meanwhile, live on a 13-year cycle and emerge over a much larger geographic area that includes Illinois, Missouri, Louisiana, North Carolina, Virginia and Maryland.
Seven broods of periodical cicadas make their home in North America, and depending on the species, they emerge every 13 or 17 years. Occasionally a 13-year brood and a 17-year brood hatch at the same time, but each particular pairing only sees their cycles align once every 221 years.
This year’s event is unusual because these particular hatches are synchronizing and also because they happen to be close together, with a narrow geographic overlap area in central Illinois.
“There aren’t many places in the country where two very different broods overlap,” said Daniel Young, a professor of entomology at the University of Wisconsin-Madison and director of the school’s insect research collection.
Thousands of cicada species can be found around the world, but periodical cicadas are different because they spend most of their lives underground, feeding on tree roots. After either 13 or 17 years, depending on the brood, the insects tunnel to the surface to begin a frenzied, month-long search for a friend.
Louderman said he has yet to see any reports of a chickadee sighting early on. The insects usually emerge from the ground when the soil temperature reaches about 64 degrees Fahrenheit.
Some could start emerging in early to mid-May, Louderman said. That should continue into June with warmer conditions. Once the insects are out in full swing, he and his colleagues will travel around Illinois to collect specimens for the Field Museum’s collection.
Chickadees are perhaps best known for the racket they make above the ground. The insects’ mating song, a high-pitched buzz, is hard to ignore and can reach up to 100 decibels.
“There are just so many of them that the noise is almost deafening,” Louderman said. “It’s like 1,000 chainsaws going off and they’re all being used at the same time.”
The insects have a few chaotic weeks to find a mate and lay their eggs before they die. Afterwards, people are likely to see a large number of insect carcasses littering the ground.
“They will literally pave the sidewalks and streets — it’s just crazy,” Louderman said. “Some people get really excited about it.”
But, cicadas don’t necessarily bite, Louderman said.
He describes himself as a “lifelong cicada enthusiast” and said his passion was sparked after an early brush with the insects.
“A cicada came up periodically when I was 8 years old, and that got me into insects and entomology,” Louderman said.
In the same way that the total solar eclipse surprised many this spring, he said, some young people may be interested in the evolution of the chickadee and even decide to continue their field of study.
At the University of Wisconsin-Madison, researchers plan to track where cicadas are seen to map their range. Young is also encouraging others to join the task.
People in the Midwest and Southeast can take pictures of cicadas in their area and report the sightings on an app called Cicada Safari or on websites like Bugsinourbackyard.org or Bugguide.net.
Young said he hopes people will take the opportunity to experience the rare and significant event, especially in the parts of Illinois where the two cicada broods overlap.
“Not many people in human history will be in a place where they can see that,” he said. “A lot of people might find it very incomprehensible, but it’s really amazing.”
This article was originally published on NBCNews.com
