In its next installment of the McLib Evenings Upstairs series, the McCracken County Public Library will host Woodlands Nature Station's Public Programs Coordinator, Nickolaus Willis, for a presentation titled "What's All the Buzz? Nature's Big Cicada Emergence 101" on Thursday, July 18, at 5:30 pm. WKMS Morning Edition host Daniel Hurt speaks to Willis about the insects, their complex lifestyle, and their impact on Kentucky's environment.
With a rare double brood emerging in the eastern United States, these noisy insects have been seen all over the news. "The ones we heard this year are kind of special compared to ones we hear every year. The ones we hear every year are the annual or dog day cicadas. But the ones we had this year, we had what are called periodical cicadas. Those guys come out every 13 to 17 years, depending upon which brood we're talking about and which species we're talking about,” Willis explains.
The special brood has already passed, but the buzzing heard outside recently are dog day cicadas. "The ones we're hearing now, we'll continue to hear through the rest of the summer. [These] regular yearly dog day cicadas are what some people call jar flies. Earlier this year, between April and June, we were hearing the two separate emergences of periodical cicadas. This evening, that's what I'll be going over, showing off some of the cool pictures and sounds and maps of all this and all the work everybody's done over the last, you know, 100 or more years to figure all this stuff out."
"Periodical cicadas are endemic to just here in North America," Willis continues. "We're not going to find those anywhere else in the world. We're already special in that regard. But the two broods that came out this year, we had Brood XIX, the Great Southern Brood. That's one of the 13-year species. [Brood] XIII in northern Illinois, this is one of the 17-year species. They both came in 1803 and are considered very large broods. Brood XIX covers the largest geographical range of any periodical cicada. Brood XIII, the northern Illinois brood, is the largest emergence as far as numbers of individual cicadas coming out. They can range from tens of thousands or more."
"We get cicadas every year, but those are the annual ones, and they tend to be a bit more cryptic. They're not as loud as their periodical cousins. They're not trying to get all the attention. These periodical ones are very different, and the current hypothesis is that by coming out every 13 to 17 years, most predators don't adapt to them even existing because any would-be predators trying to wait that out are going to have to find a different food source," he explains. "None of those potential predators—birds, dragonflies—really adapted to look for those periodicals. When they do come out, they come out in such overwhelming numbers that the predators get filled up on them pretty quick, no matter how tasty they are. Think of it as the air suddenly swarmed with billions of Hershey Kisses. Eventually, you're going to get tired of eating chocolate."
Willis says cicadas have a relatively short adult lifespan. "Cicadas are unique among insects in that they spend 99% of their life in their nymph and larval stages. They come out of the ground, and within two or three months, they're done with their adult stage already. Most insects have it kind of the other way around. Their larval stages are a bit more brief, then the adult stage lasts a while."
These insects are also a good indicator of a healthy forest ecology. "They feed on the sugary tap in the trees, even the periodical ones, for the 90+ percent of their life that they spend underground," Willis says. "They are attached to the root system, and they play a vital role, and having these healthy populations of both the periodical cicadas and the annual cicadas lets us know that our trees are doing well and that our overall soil ecology is allowing these kinds of techniques to thrive."
"I'll go into greater detail about all these bullet points but [will] also have some fun images and wonderful sounds. These insects are well-known for the racket they make. We'll play some of that because that also varies, and then I'll talk about some maps that show what we can expect from these critters over the next few generations," Willis concludes.
The McCracken County Public Library presents McLib 101: What's All the Buzz? Nature's Big Cicada Emergence 101, led by Woodlands Nature Station's Nickolaus Willis, this Thursday, July 18, at 5:30 pm. The event is free and open to the public. To learn more about this event and other library programs, visit the McLib website.
