This time next year, certain parts of the country will experience something so unique it hasn’t occurred since 1803: The emergence of periodical 13-year and 17-year cicadas will coincide. But Chicago might be able to welcome some of these cicadas as early as this Memorial Day weekend.
“They come up together like this once every 221 years,” said Gene Kritsky, dean of behavioral and natural sciences at Mount St. Joseph University in Cincinnati, Ohio. “So next year, when the two broods emerge — the last time that happened between these two groups, Thomas Jefferson was president of the United States.”
Love them or hate them, Chicagoans might not have to wait another year to see the blood-red eyes of these polarizing creatures with orange wings. It often happens that a few hundred stragglers get confused and emerge a few years before or after they are supposed to.
Scientists are expecting an early emergence of brood XIII cicadas, which come out every 17 years, and of brood XIX cicadas, which come out every 13 years. The former can be found in northern Illinois, including the Chicago area, as well as in some parts of Iowa and northeastern Indiana. The latter can be found in various southern states, including south portions of Illinois.
Kritsky said these early cicadas will likely be eaten by birds, cats, squirrels, raccoons and similar predators — who should consider this year’s insects “hors d’oeuvres” in comparison with the numbers expected next year.
“The (stragglers) are numerous enough to be noticeable but they also don’t really survive very long because the periodical cicadas sing during the daytime when birds and other predators are quite active, and they’re relatively obvious insects,” said Phil Nixon, retired entomologist from the University of Illinois at Urbana-Champaign.
According to Kritsky, cicadas usually come out after a day or two of high temperatures in the low 80s and low temperatures around the 70s, followed by rain that softens the soil. They emerge after soil temperatures exceed 64 degrees.
For cicada enthusiasts and skeptics alike, the emergence of stragglers raises the question of how weather and, more specifically, warming global temperatures might have an impact on periodical cicadas’ life cycles.
“One of the weird things going on in Chicago, in particular, is that large numbers of cicadas are coming up for years ahead of schedule,” Kritsky said. “That happened three years ago in 2020. We had so many cicadas emerging in Greater Chicago. They sang, they mated, they reproduced — that was unexpected.”
But, he pointed out, something similar happened in 1969 when some brood XIII cicadas came out four years ahead of schedule. “That’s a genetic switch,” he said. “We don’t know for sure, but it’s very likely a genetic switch that’s triggered.”
The emergence of periodical cicadas during earlier months in a given calendar year might also be evidence that temperatures affect the insects. For example, weather may affect the flow of tree fluids that they feed from.
“Periodical cicadas in Chicago and elsewhere, they’re emerging two weeks earlier than they did back before 1940,” Nixon said. Whereas they would historically emerge on the first week of June, more recent cicadas have emerged as early as the last week of April.
“And that would definitely be an example of how climate change and gradually warming temperatures will have an impact on them,” he added. “Global warming could affect (early emergence), but I don’t know that that’s been determined. Two hundred years ago, there were stragglers as well.”
Though it remains a mystery precisely how periodical cicadas know when to emerge, ordinary citizens can contribute to their study by getting up close and personal. The good news is the insects are all bark (buzz) and no bite: They do not sting or carry diseases.
By downloading Mount St. Joseph’s popular Cicada Safari app
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from the Apple App Store or Google Play into a smartphone, people can contribute by tracking, mapping, photographing and recording the stragglers coming to town next week. This allows scientists to determine the distribution of the emerging cicadas.No matter whether you like cicadas or not, the stragglers coming to Chicago in the next week or so will be an early taste of what’s to come in 2024.
“Some people will consider them to be the most obnoxious thing in the world. This earsplitting noise — and when they’re very numerous in a major year, it is deafening,” Nixon said. “And they consider them to be just a horrendous thing. On the other hand, I’ve had a lot of calls from people who want to know where they might be able to go collect cicadas.
“They want to go collect them and bring them back and try to get them started in their yard because they think that one of the most wonderful things that nature could have are these things that come out every 13 or 17 years … And they consider rather than their song being a terrible, noisy din to really be a melodious song that they really enjoy and cherish. So it’s all in the ear of the beholder, so to speak.”