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In this Episode meet

The Two-sided Story of Periodical Cicadas

Produced and hosted by Jonathan Yales - 37 min.

Any day now, periodical cicadas will emerge across 15 states stretching from Illinois to New York and northern Georgia.

Two scientists, one who’s tracked the aboveground movements of these cicadas, and another who’s unearthed the belowground impact of these insects, take you inside the many mysteries and forgotten elements of these evolutionary enigmas. 

Forestcast is looking for listener cicada recordings! You may be a part of an upcoming episode, record cicadas chorusing around you, tell us where you are and who you are. Just record your cicadas on your phone and send them to: sm.fs.nrsweb@usda.gov.

JONATHAN YALES

HEY, IT’S JON.

I JUST WANTED TO POP IN HERE REAL QUICK AND LET YOU KNOW, WE HAVEN’T GONE ANYWHERE. SEASON TWO OF FORESTCAST IS STILL COMING—SO STAY TUNED.

BUT, ALSO… TODAY... I HAVE SOMETHING SPECIAL FOR YOU.

YOU'RE PROBABLY AWARE BY NOW THAT A TON OF CICADAS ARE SCHEDULED TO EMERGE SOON. THERE'S NO DOUBT YOU'VE SEEN SOME OF THE STORIES.

BEING THE FOREST SERVICE, WE COULDN'T NOT DO AN EPISODE ON CICADAS, BUT HOPEFULLY, I HAVE A STORY TODAY THAT'S A LITTLE DIFFERENT THAN EVERYTHING YOU'VE HEARD SO FAR.

A STORY THAT TAKES YOU SOMEWHERE THAT YOU OVERLOOK.

LET'S DIG IN.
LITERALLY.

JON
Hello?
MAC CALLAHAM
Hello, this is Mac.”
JON
Hey, Mac. How's it going? This is Jon from the U.S. Forest Service. I don't know if you could hear me right there?

THIS IS MAC CALLAHAM. A RESEARCH ECOLOGIST WITH THE SOUTHERN RESEARCH STATION IN ATHENS, GEORGIA.
MAC
You know, I've been digging holes and thinking about all the insects and other arthropods, and annelids, and everything that lives below ground for a long time now.
JON
EVEN THOUGH IT’S 99% OF THE CICADA’S LIFE, THE BELOWGROUND SIDE OF CICADAS IS FORGOTTEN BY MOST.
MAC
The fact that these organisms—the cicadas—spend most of their lives, the giant fraction of their lives, below ground is something that a lot of people don't really think about much, you know? So, they live for 17 years, but they're only above ground for about three weeks of that 17 years.
JON
BUT, WE’RE ALSO NOT HERE TO IGNORE THEIR ABOVEGROUND LIVES, EITHER.
SANDY LIEBHOLD
I'm interested, of course, in insects, but I'm also interested in spatial patterns
JON
THIS IS SANDY LIEBHOLD, A RESEARCH ENTOMOLOGIST IN MORGANTOWN, WEST VIRGINIA.
SANDY LIEBHOLD
So, I'm interested in spatial patterns of insects, which maybe for other people doesn't sound so exciting, but for me really, it kind of turns me on.”
JON
SANDY’S BEEN TRYING TO UNDERSTAND THE CICADA’S ABOVEGROUND MOVEMENTS FOR DECADES.
SANDY
To me, this question of why are periodical cicada broods shaped the way they are, and why do they not overlap, this is something that I've really wondered about for many years and thought it was really cool.
JON
BUT, BEFORE WE GET ANY FURTHER ABOVE OR BELOW GROUND, WHAT IS A CICADA?
SANDY
Cicadas are a family of insects, and they're distributed all over the world. They're a type of sap-feeding insect. They basically survive by sucking plant fluids. And so, in the case of cicadas, they spend most of their life as nymphs—that is immature stages, living underground feeding on the roots of plants—and as adults they emerge and they can fly and they feed on sap of plants also. And, there are actually a lot of insects that feed on roots, and the thing is, you don't notice them very often, just because, obviously, if they're living underground, you don't see them.
JON
ONE THING I SHOULD POINT OUT, TOO, IS THAT THERE ARE “ANNUAL” CICADAS, WHICH ARE ALL OVER THE COUNTRY, ALL OVER THE WORLD, AND, AS SANDY SAID. THEY LIVE UNDERGROUND, EMERGE ABOVEGROUND, MATE, AND DIE, ALL WITHIN A FEW YEARS.
 
BUT, THEN THERE’S “PERIODICAL” CICADAS, WHICH EMERGE EVERY 13 OR 17 YEARS. AND, THEY’RE NO WHERE ELSE IN THE WORLD THAN EAST OF THE PLAINS IN NORTH AMERICA.
 
TODAY, WE’RE MAINLY TALKING ABOUT PERIODICAL CICADAS.
 
SO, LET’S HEAD UNDERGROUND WITH MAC, TO GET A CLOSER LOOK.
MAC
The whole system is really unbelievably fascinating to me because, you know, what they're doing belowground is they basically drill into the tree root. And they don't eat the part of the tree root that is moving the high quality stuff around, right? So, roots—the tree roots—have the same parts as the aboveground parts of plants, right? They've got xylem and phloem, and the phloem vessels are the ones that are moving the good stuff, right, the sugars that are getting produced in the leaves get transported through phloem, down into the tree, and the tree uses that for growing new roots and whatever else—all that's being done in the phloem. All the xylem has in it is water, that has been taken up from the soil around. And, the cicadas pierce into the xylem vessel, and they basically just pump water through their bodies. And, somehow, by some mechanism—which I don't think is well understood—they manage to get enough nutrients out of that xylem water, which is basically pure water, right? It might have a very little, dilute amount of amino acids in it for, like, 90% of the year. The only time the xylem has anything good in it is during the spring when they're flushing new leaves. So, all the stuff that's stored below ground gets put into this xylem and then moved back up out into the canopy of the tree. So, they’re potentially only getting decent food for two weeks out of the year when that spring flush is happening, and then the rest of the time, they're just pumping water.
JON
BUT, WHY, ONCE THEIR 13 OR 17 YEARS ARE UP, DO THEY EVEN COME UP? WHY CROSS OVER FROM BELOW GROUND TO ABOVE GROUND IN THE FIRST PLACE?
 
SANDY
Well, they have to mate. Like any other animal, they have to mate, and they have to have babies. And so, the nymphs live underground, but obviously, only adults can mate. And the adults, they fly, and so this means it’s something that has to happen above ground. And so, early May they start tunneling towards the surface and they form a little chamber where they go through their last molt between their last nymphal stage and they develop into an adult. And then, they will then burrow out through the ground and emerge as adults. The kind of spectacular thing about this is that it usually happens in just a couple days, that most of the cicadas in an area emerge in just two or three days. And so, it's a rather spectacular thing. You see them crawling out of the ground and then they crawl up the trunks of trees.
JON
AND, TO MAC, THE RESULT OF THAT ON THE SOIL, IS FASCINATING.
MAC
They all decide they're going to come up at the same time, and they just burrow their way up, leaving a big hole. And, that's to me, that's really, as a soils guy, that's really something that I think is truly remarkable is when you look down on the surface of the soil, after an emergence, it literally looks like Swiss cheese. There's holes—big holes—everywhere. And, that's another thing that we're really interested in, right? So, what does all that new bore space in the soil mean in terms of gas fluxes and water infiltration.
JON
THIS IS THE PART OF PERIODICAL CICADAS THAT IS OFTEN OVERLOOKED. ONCE THEY’RE UP ON OUR PLANE OF EXISTENCE—ABOVEGROUND—WE TEND TO JUST FOCUS ON WHAT THEY DO THERE. WE TEND TO FORGET THE PATH THEY TOOK TO GET ABOVEGROUND, AND WHAT THAT BELOWGROUND TRIP ENTAILED.
MAC
The one thing that we know happens is that material from the surface of the soil, eventually, kind of backfills into the emergence holes, and what that amounts to is, you know, over time, if you do the math, if you think about stuff from the surface falling into those holes and filling them back up, that amounts to a turnover of the surface soil. So, eventually, the entire surface of the soil will have either fallen in from the surface into a hole and then pushed back up and around like a conveyor belt. And, I did some back of the envelope kind of calculations and estimated that, like, the top three feet of soil are turning over 100% entire turnover in about a thousand years, due, strictly, to cicada activity. So, that has significant consequences for the incorporation of organic matter from the surface into the soil and overall nutrient status of that soil. So, you know, I don't have a thousand years to study it, but it's fun to try and do, like I say, these back of the envelope kinds of calculations to see what the real impact of cicada emergences are on the soil system.
JON
And, how does that number—a thousand years—compare to, like, not having cicadas? Like, why is it fascinating to you?
MAC
Yeah, well, yeah, so, I mean—Jon, you don't really want to get me going on bioturbation as a soil process.
JON
No, please, this is what Forestcast is for.
MAC
You know, because, there are a lot of creatures that do this process, right, that take soil from below ground and move it above ground, or vice versa, take material from above ground and move it below ground. And so, the big three are earthworms, termites, and ants are considered to be the big bioturbators. And so, I think the big deal with cicadas is that they're doing it in a way that is much more profound, in terms of soil depth, right? So, none of the earthworms or ants, they're not doing anything deeper than maybe three inches, four inches deep.
JON
Wow!
MAC
Really
JON
I didn’t know that.
MAC
Some, but not much. Yeah. But the cicadas, the fact that their tunnels are meters long, two meters long, I mean, that's something that no other creature is doing in those ecosystems. Bioturbation of soil is, I think, kind of an overlooked process, and it's overlooked because it's done by very small creatures over very long periods of time.
JON
BOUNCING BACK NOW ABOVEGROUND, TO OUR CICADAS THAT ARE JUST EMERGING, HOW DOES THAT LOOK? NOT FROM AN INDIVIDUAL SENSE, BUT FROM A MACRO SENSE? SANDY KNOWS.
SANDY
Even though locally they're synchronized to all emerge in the same year, the development is actually not completely synchronized over, like, thousands of kilometers, and instead, you have these little pockets that we refer to as “broods,” and these broods cover a geographical area of 30 miles apart, or they might be 200 miles in diameter, and these are basically areas—regions—where the populations are synchronized, such that they emerge in a given year. But then, you find these boundaries where you pass from one brood to another. So, you may be in one part of North America where they're emerging in one year, you may travel 10 miles across a border and they will emerge maybe three or four years later. If you look at the entire map of the U.S. and where these broods are located, they sort of fit together like little puzzle pieces, because there are very few cases where broods overlap—there's almost no overlap of these broods. Some of them are big and some of them are small.
JON
WE MIGHT NOT KNOW EXACTLY HOW STATIC THESE BROOD BOUNDARIES HAVE BEEN, BUT WE DO HAVE RECORDS GOING BACK ABOUT A HUNDRED YEARS TO TRY AND COMPARE.
SANDY
The first attempts to actually map the brood boundaries go back to around the early 1900s. There was a USDA scientist, Charles Marlett, and he was the first person to put together a map of the U.S. showing the years that broods emerged, and he's the one who came up with this numbering system that we use for numbering the timing of the broods based on using Roman numerals. And, the kind of cool thing is, if you look at the map that Charles Marlett made back in 1911 that showed that distribution of brood boundaries, it's pretty much where the broods are now. And in some ways that might seem incredible, that it's like, ‘Wow, 1911 to 2020, they haven't hardly changed,’ but, from the perspective of periodical cicadas, it actually hasn't been that long. You know, let's see, 1911 to 2020 is only somewhere around 15 generations of periodical cicadas. So, it's really not that long.
JON
FOR THE PAST THREE DECADES SANDY’S BEEN TRYING TO ZERO IN ON THESE BROOD BOUNDARIES. TRYING TO UPDATE, AND PERFECT, THAT MAP.
SANDY
We had an emergence, I think, I should go back and look at my notes, but I think it was 1992 and it was Brood V, which covers a lot of northern West Virginia. And I thought, ‘Wow, it's really cool,” and I began reading up about them and learned more about the broods. And so, I thought, ‘Well, it'd be really interesting to try to characterize the boundaries of broods.’ And so, my assistant, Gino Luzader, who worked with me in the Forest Service, we came up with this system for mapping brood boundaries using a GPS technology—which back in like 1992 was a fairly new thing that not many people had been using—and in fact, back then, the military was still scrambling GPS signals, but in the Forest Service, we had this special GPS unit, that was like an Army GPS unit, and so it had the secret chip in it that allowed you to get the more accurate spatial locations from the GPS unit. And, so, we came up with this system where we would drive around, in an area in a general area—and this area, we looked at the historical brood maps and realized that in-between Morgantown West, Virginia and Pittsburgh, Pennsylvania is roughly where the boundary between Brood V and Brood IX is—and we got in a car and started to drive around—and this is during the period of the month-long adult immersion period, Brood IX—and we drove around in that area and we would stop every, maybe, quarter of a mile and listen for cicadas. And, if we were in a chorusing center, we’d push one button on the GPS, and if we did not hear a chorusing, we pushed another button on the GPS. And, by spending, maybe a week driving around along this boundary, we were able to come up with a pretty good map of where the boundary, at least, where this Brood V ended.
JON
AND, SINCE THE 90’S, SANDY’S BEEN CONTINUING THAT RESEARCH TO FURTHER PERFECT THE MAP, AS WELL AS TO TRACK HOW MUCH THE BROODS MOVE.
SANDY
So, then we ended up doing the same thing four years later when Brood IX emerged, and then we did it again 17 [years] later for the next emergence of Brood V, and four years again after that, which was just, I think, two years ago—2019 was our last measurement. And so, it's pretty cool, we've been able to actually get a very precise picture of where the boundary is for both Brood V and Brood IX. And, when you look at them, they again, they sort of fit together almost like pieces of a puzzle—where one boundary kind of sticks out in a peninsula, it's sort of a bay for the other brood, and vice versa. But, we did actually find a little bit of overlap—there actually are a very few places where we would find a Brood V, and then we’d come back four years later and find Brood IX. So, they only overlap by, maybe, anywhere between zero and, maybe, half a kilometer in that area.
JON
And, we've talked about other insects, and people have tried to see, like how far does an emerald ash borer move, how far does a gypsy moth move? Do we, either from your own work or just from knowledge of other research, do you know how far cicadas move?
SANDY
Well, periodical cicadas can fly, I mean, they have wings, and we know they're probably capable of flying, probably, several hundred meters. They're not great flyers, because again, they're sort of like these big blimps, so they're not great flyers, but they do fly. But, the other—a few things are that probably prevent them from moving long distances in many situations, one is, basically, they have this behavior, they like to aggregate. And, part of this is driven by the chorusing—by the sound—that mostly the males produce. So, the males chorus and they attract other males, and then the males start to form this big group, and then they make a big noise together, and that's very attractive to females, and so, the females are attracted to these big groups. So, all of those behaviors together drives cicadas to be near each other, so, they don't have a very, sort of, innate behavior to move away from other cicadas, instead they like being around other conspecifics.
JON
BUT, THERE’S ALSO ANOTHER REASON THAT THESE BLIMPS PROBABLY DON’T MOVE THAT MUCH, ONCE ABOVEGROUND.
SANDY
The other thing though, which is interesting—and I've actually been working with applied mathematicians on this, too—is to try to better understand the population processes that drive this brood boundary formation. And, one of the things that we've learned is that this very strong predator satiation phenomenon, is one of the most important things in terms of demography of periodical cicadas, is that they're an insect that does not do very well at low densities, and that's because, if a bird predators are there and they find a cicada, you know, one cicada is almost for sure going to be eaten, but when you have, instead you have, like a 100,000 cicadas in one area, then that's way too many for birds to eat all of them, and so, you'll have a good number of them to survive. And the consequence of this is that, if you were to have, say, just even a few cicadas to venture off beyond their normal boundary of their brood into sort of this new territory, they're not going to do very well because the birds are going to eat them up. And so, this behavior and this population phenomenon, it causes sort of the reinforcement of this brood boundary. And so, using mathematical models, we can show that it's very unusual to have—if the individual cicadas move outside of their brood, it's very unlikely that they'll survive.
JON
NOW, MAC’S ALSO STUDIED THESE CICADAS ABOVE GROUND. BUT, HE’S STUDYING THEM FOR A DIFFERENT REASON.
MAC
I've actually been able to do pretty careful study of two emergences of the Brood IV cicadas out in Kansas, at a place called Konza Prairie Biological Station.”
JON
KONZA PRAIRIE IS IN THE FLINT HILLS OF NORTHEASTERN KANSAS, THE LARGEST REMAINING AREA OF UNPLOWED TALLGRASS PRAIRIE IN NORTH AMERICA.
MAC
I went to Kansas because I was interested in disturbance ecology and native earthworms, so, I was an earthworm guy straight up. And, the reason to go to Kansas was because somebody had kind of laid the groundwork on a lot of the native earthworm ecology at Konza Prairie. And so, it seemed like a good place for a guy like me at that time to go.
JON
AND, IT’S IN THIS PLACE MAC HAD AN EPIPHANY.
MAC
When I got to Kansas, the guy who was my boss—my major professor—basically, handed me a map of the research site and said, ‘Here's the keys to this Jeep’—it was kind of a rattletrap Jeep that didn't have any doors on it—and he said, ‘Just go drive around out there and see if you can, you know, come up with any good questions.’ Which I thought was a really great way to approach it, right? So, I'm just driving along and I've, literally, been there for like maybe a week or two weeks, and I was driving around out at the research site, and one of these—not a periodical cicada, but one of the annual cicadas, and these things are gigantic, they're like seven centimeters, which is like two and a half inches long—comes flying along. And, you know, I saw it take up out of the grass, and it was flying, kind of, on an intersection course with me. And it flew in through the passenger side and hit me right in the side of the head. And, it was kind of a jolt, right? And, uh, I said to myself, I said, ‘Wow, that's a lot of biomass. I wonder if anybody”—and I knew, I knew enough about—
JON
That’s what you said when it hit you in the head?
MAC
I know, I know. I'm not ashamed of the fact that I'm a geek. But yeah, so, I was just like, I knew enough to know that they live belowground for most of their lives, and I just started kind of, cogitating on whether or not anybody had ever looked at it: what the, you know, the ecological term is, ‘emergence production,’ how much biomass do they produce on an annual basis? And so, I did a little bit of digging and it turned out that nobody really had.
JON

BUT, HE HAD TO WAIT.

TO STUDY CICADAS, THEY GOTTA EMERGE, AND TO STUDY PERIODICAL CICADAS, YOU REALLY GOTTA WAIT.

AND, ONCE 2015 HIT, BROOD IV IN KANSAS WAS SCHEDULED TO EMERGE.

SO, MAC WENT BACK OUT.

MAC
When we knew the emergence was about to happen, we went out into the gallery forests, so this landscape is mostly grassland, but in the creek valleys, there is lots of woody vegetation—they call them gallery forests because they kind of run in galleries along watercourses. And so, we knew that because these periodical cicadas, because they're obligate tree feeders, we knew pretty much where we were going to need to look for them. So, we went to the gallery forests, and we just set out traps—emergence traps—so that when they came up out of the ground, we would be able to collect them and come up with some kind of estimate of how many there were per unit area, and then we could take the trapped individuals and weigh them and analyze their bodies for carbon and nitrogen content, and that way, be able to scale up, sort of, to what the full effect of the emergence was going to be on those cycles on the carbon and nitrogen cycles.
JON

THEY ENDED UP TRAPPING ABOUT 1,300 CICADAS ACROSS A TOTAL AREA ABOUT THE SIZE OF A MIDDLE-CLASS LIVING ROOM. AND, THEY THEN USED THAT DATA TO ESTIMATE HOW MANY CICADAS MIGHT HAVE EMERGED ACROSS THE ENTIRE STUDY AREA—WHICH WAS ABOUT THE SIZE OF 300 FOOTBALL FIELDS.

AND, THE NUMBER THEY CAME UP WITH? 35.2 MILLION CICADAS.

IN 2015, IN A COUPLE CREEK VALLEYS, IN A SMALL POCKET OF KANSAS, AN ESTMATED 35.2 MILLION CICADAS EMERGED.

AND, IF YOU BREAK THAT DOWN TO A SINGLE FOOTBALL FIELD AVERAGE, IT’S ABOUT 117,000 CICADAS PER FOOTBALL FIELD.

AND, AS MAC SAID, THE REASON HE WANTED THAT INFO WAS IN ORDER TO START TO ESTIMATE WHAT THAT MASSIVE AMOUNT OF BIOMASS DOES TO THE SOIL, AND TO THE ECOSYSTEM.

WHERE DOES IT ALL GO?

MAC
And so, what we found was that in some places the amount of Cicada biomass was something along the order of maybe 30 kilograms of nitrogen per hectare was coming from belowground to aboveground. And so, to kind of put that into perspective, the other people who've been working there have been working on the nitrogen cycle for a long time and so they have good estimates of what you might expect to be input into the system in a single year. And that number ranges—depending on how much precipitation there is and how much dust gets blown in and how much sort of in situ fixation of nitrogen is happening in the microbial community—and the estimates range from like, I think 11, to maybe, 25 kilograms per hectare per year. So, if you have a cicada emergence that's accounting for 30 kilograms per hectare in one year, that's a non-trivial fraction of the total amount of nitrogen that that system might be receiving. And so, you know, it kind of begs the question, like, what happens to that nitrogen that has suddenly emerged in the form of cicada bodies? That'll be the next phase of work that we do is to try and see exactly where the cicada nitrogen goes.
JON

BUT, THAT NEXT PHASE OF RESEARCH COULDN’T BEGIN FOR ANOTHER 17 YEARS.

TO STUDY CICADAS IS AUTOMATICALLY LONG-TERM RESEARCH. NOW, WE’RE USED TO LONG TERM RESEARCH IN THE FOREST SERVICE, AND IN FORESTRY. BUT, JUST THINK, WHAT IF THE TREES YOU STUDIED ONLY APPEARED EVERY 13 OR 17 YEARS? IT’D BE PRETTY HARD TO BE A FORESTER.

MAC
You know, I'll be in my early sixties when the next periodical emergence happens. So, really, I, you know, if I can still get around pretty well, I do fully intend to go back and do one more round of study at Konza Prairie. I really do, kind of, see it as something that I might revisit, maybe, when I retire from the Forest Service.
JON
Do you have any plans to do any other research, either on Brood X that Sandy talked about, because that does dip right into the north part of Georgia?
MAC
It will extend down into some of the northern tier of counties in Georgia. And, in fact, a colleague of mine and I—a guy named Bruce Snyder, who’s at Georgia College & State University in Milledgeville—he is a belowground ecologist, and enthusiast, like myself, and so, we kind of dug around and found some records of Brood X a little bit further south than we originally thought. And so, one of the things that we'll do—we'll definitely do—is try to visit many of the sites where the Brood was observed in the previous emergence and just to confirm or deny that they're there, and then, if we can identify some places, we will certainly try to go and do some similar work to what we did in Kansas, which is to go out and try to come up with some kind of an estimate of their population numbers and density, and then we can do—again, this'll be kind of back-of-the-envelope fashion, but—we can do some estimates of carbon and nitrogen movement associated with the Brood X emergence.
JON
Do you mind if I give you guys a call or something when you're doing that?
MAC
No, no way. That'd be great.
JON
Okay. Maybe, I'll check in later, later on in the spring, to see, kind of, how that went, or how that’s going.
MAC
Yep, sure thing, man.
JON

I’M GOING TO TRY TO TOUCH BASE WITH MAC WHILE HE’S DRIVING AROUND LOOKING FOR CICADAS. LOOK FOR A SPECIAL EPISODE IN A MONTH OR SO, IF HE FINDS ANYTHING.

ALSO, IF YOU WANT TO BE A PART OF THAT EPISODE, SEND ME YOUR OWN FIELD RECORDINGS OF YOUR OWN CICADAS. THEY CAN BE ON THE SIDE OF A ROAD, IN A PARK, OR IN YOUR OWN BACKYARD. RECORD WHERE YOU’RE AT, AND WHO YOU ARE.

JUST RECORD THEM ON YOUR PHONE AND SEND ‘EM TO ME AT SM.FS.NRSWEB@USDA.GOV, OR SHARE ON TWITTER: @USFS_NRS.

I’LL BE WAITING.

AND, THANKS FOR LISTENING

REAL QUICK, ONE CORRECTION, SANDY MISSPOKE EARLIER. AFTER OUR CONVERSATION, HE REFERENCED HIS RESEARCH MATERIAL AND RECALLED THAT HE DIDN’T START HIS BROOD BOUNDARY PROJECT IN 1992, HE STARTED IT IN 1999. AND, HE WAS TRACKING BROOD V AND BROOD VIII, NOT BROOD V AND IX.

THIS EPISODE WAS PRODUCED, EDITED AND WRITTEN BY ME, JON YALES. MY EDITORS AT THE NORTHERN RESEARCH STATION WERE JANE HODGINS, SHARON HOBRLA, AND GINA JORGENSEN.

SPECIAL THANKS TO MAC CALLAHAM OF THE SOUTHERN RESEARCH STATION. AND SANDY LIEBHOLD OF THE NORTHERN RESEARCH STATION. AND AS ALWAYS, THANKS TO OUR FRIENDS AT THE MICHIGAN STATE UNIVERSITY DEPARTMENT OF ENTOMOLOGY.

SANDY
Actually, this guy, Charles Marlatt…
JON
Yeah?
SANDY
I mean, don't get me started on this [laughs]. He's, like, a really interesting person…
JON

IF YOU WANT TO LEARN MORE ABOUT THIS GUY MARLATT, THE GUY WHO MADE THE FIRST MAPS OF PERIODICAL CICADAS, SANDY WROTE A WHOLE PAPER ON HIS LEGACY. THE MAN HAD CARVINGS OF PERIODICAL CICADAS IN HIS BANISTERS. AND, HE WAS A WILDLY IMPORTANT FIGURE IN EARLY DAYS OF THE USDA.

SEARCH: “THE LEGACY OF CHARLES MARLATT” TO READ MORE.

ALSO, IF YOU HAVEN’T YET WRITTEN A REVIEW FOR THIS PODCAST ON APPLE, GO DO IT, PLEASE. IT HELPS MORE PEOPLE FIND THE POD. WRITE A REVIEW, LEAVE US A TOPIC YOU WANT COVERED, WHATEVER YOU WANNA WRITE.

THIS PODCAST IS PRODUCED BY THE FOREST SERVICE, AN AGENCY OF THE U.S. DEPARTMENT OF AGRICULTURE. THE USDA IS AN EQUAL OPPORTUNITY PROVIDER, EMPLOYER, AND LENDER.

AND THIS EPISODE’S MUSIC WAS BY BLUE DOT SESSIONS.

THANKS FOR LISTENING.

[CICADA AMBIENCE]

 

Meet the Scientists

Research Entomologist Andrew (Sandy) Liebhold While Research Entomologist Sandy Liebhold is fascinated by periodical cicada, most of his research focuses on understanding ecological processes operating during the arrival, establishment, and spread phases of biological invasions. One of the aspects of periodic cicada that makes them not only fascinating but relevant to his research is the population interactions that govern range boundaries in periodical cicadas.


Research Ecologist Mac CallahamA Project Leader/Research Ecologist for the Forest Service's Southern Research Station, Mac Callaham is interested in soil. His work focuses on how forest management activities such as tree harvest, thinning, and prescribed burning affect soil and the endlessly fascinating organisms that are at home in soil, such as insects, earthworms, and a whole host of microbes.


Images

Adult Cicada
Brood X cicada on leaves. Photo by Ken Hammond/USDA.

Map of Periodical Cicada Broods ranges.
Map of Active Periodical Cicada Broods in the United States.


Featured Science Resources

Archival Recordings

Environmental Education Resource