[music]

[cicadas buzzing]

Brigid Bergin: It's the Brian Lehrer Show on WNYC. Welcome back everybody. I'm Brigid Bergin filling in for Brian today. That buzzing you just heard was the sound of millions of desperate cicadas looking for a mate. If you live in parts of the Midwest or the Southeast, you probably know that sound and maybe considering an investment in some nice noise canceling headphones. After years underground, two massive groups of cicadas are crawling out of the earth at once from northern Illinois to the Carolinas, and they are loud.

It's been reported that it's so noisy in one part of South Carolina that some people are mistaking the sound for construction and calling the police. You'll hear some cicadas every summer. These groups, or broods, only emerge every 13 or 17 years, and it's rare for two broods to emerge at once. This is the first time these two will be emerging together since 1803. Here to explain why this is happening and the effect these bugs can have, not just on our ears, but on our ecosystem, is Vox senior environmental reporter, Benji Jones. Benji, welcome to the show.

Benji Jones: Hey, Brigid, good to be with you.

Brigid Bergin: Listeners, do you have any burning questions about this dual emergence or just about cicadas in general? Now is your time. We'd love to also hear from any listeners in the Midwest or Southeast who are seeing the cicadas, more likely hearing them, emerge around them, give us a call. 212-433-WNYC, that's 212-433-9692. You can call or text at that number. Benji, before we get into the effects of this emergence on the entire ecosystem, let's talk about the cicadas themselves. I said they're emerging from underground, but how did they get there in the first place?

Benji Jones: Cicadas are these really incredible magical and mysterious insects. When they're born, and we can talk about that in a bit, they fall as babies onto the soil, burrow down, and these are wingless nymphs as they're called, basically baby cicadas. Then they burrow into the soil and latch onto the roots of plants, of trees, of bushes. They have these straw-like mouths that extend into the roots where they suck the sap from the trees. They basically do that for many, many years, either 13 or 17 years. These nymphs are stuck on the roots of these trees, underground, out of sight, sucking the sap down and growing very slowly over time.

Brigid Bergin: You talked about how they're born. Do you want to talk us a little bit through that piece of their life cycle?

Benji Jones: They have incredible life cycle. They're staying underground for 13 or 17 years. Then when the temperature is just right, they emerge in mass and then they crawl up a tree or a blade of grass or a fence, and then they molt, they shed their exoskeleton, which is why you often see these crispy bug-like things that are empty. Then they call for mates, they mate, and then the females that are pregnant will lay eggs in the twigs of branches. They'll cut a little slit in the branches, lay their eggs, and then several weeks later, all those eggs will hatch. Researchers have described this as a snowing effect.

You have all these little white baby cicadas that are just a couple millimeters long crawling along the branches and then jumping off and floating to the forest floor because they're so light. Then if they don't get eaten by something, they will burrow down and then start that process again and just literally wait for more than a decade. It's a pretty bizarre life cycle.

Brigid Bergin: Not to sound too conspiratorial here, but 13 and 17, both prime numbers. Is there any significance to that? Do we know why they evolved to this schedule?

Benji Jones: This is one of the most fun things, I think. I don't think the prime number thing really holds a ton of water as the main strategy. What I've heard is that, essentially, the strategy is that you want to all erupt together to overwhelm your predators. If you have so many of the bugs, like the birds literally, everything goes for cicadas, everything. It's like a complete frenzy, a feast frenzy in the forest.

If you have so many cicadas all at once, some of them are naturally going to survive just because the birds can't eat anymore, and so those ones will go on to create the next generation. The 13 versus 17 years, so the thinking is that you need to have this happen very rarely so that predators can't like wise up to this and start adapting to these cycles, because if you're a bird, the chance of you experiencing two emergences in your lifetime of the same brood is almost zero.

By having these strange numbers that are really long, these long periods, it allows them to get ahead of their predators and makes it more difficult for their predators to evolve a strategy. Just on the prime number thing, scientists thought that that could have been part of what the bugs were doing as a strategy. They are emerging on these really bizarre numbers that can't be divisible, so it's harder for predators to learn.

What scientists have since learned is that you will see some cicadas, some periodical cicadas emerging on the 9-year mark or even on the 21-year mark. It seems like, and those are not prime numbers, and it seems like there is something related to the number four that is significant, but we don't really know what it is, which is again, part of the mystery here.

Brigid Bergin: Listeners, we are talking all things cicadas, and prime numbers apparently. If you have any questions for my guest, Benji Jones, Vox senior environmental reporter, about this emergence happening this summer, or if you happen to be a listener in the Midwest or Southeast who is hearing and seeing this cicada emergence around you, call us, 212-433-WNYC, that's 212-433-9692. I think you said the feast frenzy in the forest on a Friday, which is going to be one of my favorite things I heard today on the radio. When you say brood, it almost makes it sound like they're part of some extended families of cicadas, but what makes a group a brood?

Benji Jones: It really has to do with how often they emerge. whether they're 13 or 17 year, and also the geography. Within a specific brood, you can actually see different species and different species, they tell each other apart by the sound of the call that the males make. Only males are the ones that are calling and they can discern, we can't. It all sounds like just a lawnmower or whatever, but there are actually different species within broods. Brood really is referring to particular geographies and then whether they're emerging every 13 or 17 years. If you look across the Eastern US, there are 15 different broods and seven different species. This year, we're actually going to see all seven species.

Brigid Bergin: Wow. That is amazing. I want to go to Richard in Nyack. Richard has the question that I think many of us are probably wondering. Richard, thanks for calling WNYC.

Richard: Thank you very much for taking my call. I'm a standing member and I joined WNYC while listening to online with Brian Lehrer some 40 years ago.

Brigid Bergin: Oh, wow. Thank you for continuing to listen.

Richard: I was asking how did the cicadas generate the enormous sound that they reportedly generate?

Benji Jones: That's a great question. Basically, the males which are calling to attract females, they have these specialized organs that are called tymbals. Those tymbals have membranes that the bugs can vibrate. By vibrating those membranes, it creates the sound. Then also, their abdomens are largely hollow and so the sound will vibrate and then ricochet within this hollow abdomen, and that's what creates this incredibly loud noise. When the females hear that, they're like, "I'm interested, I want to mate." They will do a much more subtle sound, it's basically a flip of their wings, it's like a clicking noise. That cues the male to be like, "This female's interested in me." Then they start honing in on each other and engage in a mating ritual of sorts, and then they mate. It's a really interesting phenomenon.

Brigid Bergin: Richard, thank you so much for calling in with that question. Benji, who would we be as a radio station if we could not play some sounds of cicada flirtations right now?

Benji Jones: Let's do it.

Brigid Bergin: Let's hear a little sound those cicadas make.

[cicadas buzzing]

Brigid Bergin: Benji, I don't want to parse that sound too much, but could you hear in that the male or female sound or does it just all blend together?

Benji Jones: [chuckles] I'm not a cicada, famously, so I'm not great at telling it apart. To me, it sounds like a male to me.

Brigid Bergin: Perfect. Let's talk a little bit more about what zombie cicadas are. Can you explain that term?

Benji Jones: Oh my god, it's so wild. Basically, when you see these big cicada emergences of periodical cicadas, everything goes crazy for them, but there aren't very many predators that specialize in cicadas. They're just birds and squirrels and lizards are just eating them because they're there and they're protein-rich. The exception is a fungus called Massospora cicadina, I believe, and that actually specializes on periodical cicadas.

It's been described as a sexually transmitted infection because it will infect some of the cicadas when they emerge, and the spores have been dormant in the soil for a long time. They're on the same schedule as the cicadas, which in itself is really cool. Then once the cicadas are infected, the fungus will grow within the abdomen of the insect. It will basically break open where their abdomen is and knock off the sexual organs of the bugs.

If that is not enough, it will actually influence the behavior of the males and potentially of the females as well. It'll make the males not only call for females but call as if they were females to other males, which attracts all kinds of males to those infected males. Then they'll try to mate and then they'll get infected through the mating process, and then the fungus will grow in the other insects. The reason that they're called zombies is, for one, they're walking around without abdomens, without rear ends, and they're also doing some mind control. It's really an incredible example of evolution and, frankly, frightening.

Brigid Bergin: That feels like it should be its own horror film. Perhaps is the basis of current horror films.

Benji Jones: I think it is. [laughs]

Brigid Bergin: Listeners, do you have questions about cicadas? We're answering them now with my guest, Vox senior environmental reporter, Benji Jones. The number 212-433-WNYC, that's 212-433-9692. Benji, I want to pose a question that a listener texted. The listener writes, will they eat my tomatoes when ripe in summer in Jersey City? If so, anything I can do to prevent that from happening?

Benji Jones: I would say it's not a huge concern. There has been some cases where when the females are depositing their eggs in trees, they can damage the branches of the trees. On fruit orchards, that can be a problem. By late summer or even mid-summer, the nymphs are mostly underground, and so they might be sucking down some of the plant sap, but from what I understand, that's not a major issue. I don't think you need to use pesticides. These have been around for a very long time without causing super noticeable damage. I would say not a huge concern, but you will see some flagging or damage within tree branches that could be caused by the egg-laying of the females.

Brigid Bergin: This massive influx of bugs is definitely going to be a feast for a number of animals, as you mentioned. Which animals tend to benefit the most from this cicada emergence?

Benji Jones: Oh, yes. This is my favorite part of the emergence. Basically, you'll see-- Birds are a big one. They all will go for cicadas. It doesn't even really matter what their specialty is normally. Maybe they usually like seeds or they like plants or they like really tiny insects. It doesn't matter. All of it gets tossed out during these big emergencies because these bugs are just everywhere and they're really bad at defending themselves. It's sad, honestly. Their strategy is like, we are going to be in numbers, giant numbers. Beyond that, they don't fly very well.

They have really bright red eyes, which make them really visible, and of course, they're making sounds that are just drawing all their predators into them. It's just like everything goes crazy for them. Birds can really benefit and there's been some really interesting studies that look at some of the long-term impacts of these brief bursts of insects. You can see that some birds actually seem to inflate their population afterwards as if eating all these cicadas can actually make them produce more babies and then have bigger families. It could actually have long-term effects on some of these birds. That's one of the things that benefits.

A knock-on effect of that is when all these birds are going crazy for cicadas, the insects that they normally eat, which include caterpillars, those caterpillars get this break from their predators. The caterpillars start going crazy and you see really plump, juicy caterpillars that are just leisurely munching on leaves because they don't have to worry about the predators coming to pluck them because they're so conspicuous. You see lots of caterpillars during these emergences. That also, then, will have knock-on effects to trees because caterpillars are eating more leaves because there are more of them. That's part of it. Really big impacts on birds and the things birds eat.

One other thing I'll just mention is that there's some research that will start this summer that is looking at how the emergence of cicadas can affect ants. Ants are, as these researchers told me, unsung heroes of the forest. They play all kinds of roles, including they distribute the seeds of plants. The question that these researchers are asking is if you have all these cicadas that are giving even ants food, especially the small nymphs that I was describing that are falling to the forest floor, are the ants going to stop doing their job of distributing seeds of these flowers and therefore have some effect on the flowers? Really it is like everything is touched by these bugs.

Brigid Bergin: Wow. I want to go to a caller. Let's talk to Madeline in Ridgewood. Madeline, thanks for calling.

Madeline: Hi. I have a question because I grew up going to the Midwest for the summers, like Chicago, Michigan area. I recall hearing cicadas every single summer. That was like the soundtrack of the summer, was just like the thrumming of the cicadas in the background. I was always confused about this 17-year thing because I was like, "To me, I feel like they come out every year." What's up with that?

Brigid Bergin: [chuckles] Madeline, thanks for your question.

Benji Jones: That's another great question. You're totally right. There are cicadas out every summer and those are distinguished from these periodical cicadas, and they're called annual cicadas because you see them every summer. Now, these are not-- Their life cycle isn't annual. It's not like they're falling to the floor, growing, and then emerging every year. There are so many of these on shorter timeframes, like every four to six years, that's their life cycle that you'll see them emerge every year annually.

They are different from the periodical cicadas. They are much larger. They are much better defended against predators. There is very much a distinction between these annual versus periodical, but you're totally right. If you hear cicadas on years where you don't hear of these big brood emergences, those are just the standard annual cicadas and you can find those all over the world.

Brigid Bergin: I'm going to go to Brian in Freeport. Brian, thanks for calling WNYC.

Brian: Hi, how's everybody doing? A quick question. We left out the cicada killer wasp because you were discussing the life cycle and that's a pretty major predator. We see them all over Long Island. They're the largest wasps in North America. They catch cicadas in mid-flight and bury them about a foot deep to feed its eggs after they're laid. Can you tell us about them?

Benji Jones: That is a good point. My understanding is that the cicada killer wasps, I think they're solitary wasps and it is a bunch of different species that prey on cicadas in North America. My understanding is that those mostly are evolved to prey on the annual cicada. They're not in some way timed with the periodical cicadas. That could be another example of emerging at these random times so that they can't have this major response from their predators. Certainly, there are insects that will specialize on the annual cicadas that you can guarantee that they'll emerge every summer.

Brigid Bergin: We have actually several callers raising the question of cicada wasps, some even dealing with an infestation of them, but-

Benji Jones: Oh, wow.

Brigid Bergin: -let's go to Jenny in Yorktown Heights. Jenny, thanks for calling.

Jenny: Hi. Our town, Yorktown Heights, is undergoing a tremendous amount of development right now. We are a suburb that has a lot of trees, like thousands of trees have literally been cut down in the last, I would say, year, year and a half. How does that affect the cicada and that life cycle?

Benji Jones: That's a really great question and an open question still trying to figure out like, how are cicadas doing? How are these periodical cicadas doing, especially given that they're not above ground for so much time and trying to perfectly time their life cycle here? What we understand is that, in general, if you get rid of forests, if you replace forests with strip malls, with housing developments, that is probably not going to be good for cicadas because they really need to be feeding on the roots of trees, and then also going onto the trees later in life to lay eggs to mate, et cetera. What's kind of a wrinkle in this story is that cicadas seem to like edge forests. The edge of a forest where you get a lot of sunlight and you don't have a lot of competing shade from big canopy trees. The reason that it's an open question in terms of what the future of cicadas will be when we start developing even more of these forests and cutting down more of these forests, is that it seems that in some cases, all these fragmented forests that have a lot of edge habitats seem to be good for cicadas. It's a little bit of a mixed bag.

The reason why we see that cicadas like to be on trees that are on the edge is because, again, they get more sunlight. That signals to the cicadas that this tree is going to be able to grow really easily. Its roots are going to be intact. It's going to be in a place where the tree is healthy. It's an open question and there are also some other effects that we can talk about in terms of climate change and so forth but development, yes, it will have a negative effect, but also some positive effects too.

Brigid Bergin: I want to go to Marielle in Brooklyn. Marielle, thanks for calling.

Marielle: Hi, good morning. I just wanted to say Benji's doing a great job talking about all the science behind it. I am an urban ecologist. I also wanted to say, I heard someone calling in and asking about their tomatoes, and I want to push back on that a little bit. I think we shouldn't be worrying about all of the negative consequences. In so many ways, this is something that hardly ever happens. We will never experience this again in our lifetimes. I think people should be thrilled. It's comparable to watching monarchs migrate.

This sense of awe and wonder that we get from the natural world is so important. I saw so much of that during the solar eclipse, and I feel this could be something similar. People should have cicada parties, and invite their friends over to listen. It's something that's really incredible and wonderful and something to be enthralled by instead of scared of, which I think there's a lot of negative messaging I've seen on social media and people talking about killing them and pesticides. I just think that's absolutely the wrong way to think about it.

Brigid Bergin: Marielle, thank you so much for calling, and thanks for coming back. I know you've joined us before as a guest on the Brian Lehrer show. It's an urban botanist and ecologist, and founder of the NYC Wildflower Week. We're glad you're listening and glad you could join us for this part of the conversation.

Benji Jones: I just want to say, I really appreciate that comment and I totally agree, and I think like comparing this to the total solar eclipse is useful. Honestly, it's a rare phenomenon in the US, at least. We're not going to see this again, these adjacent broods, brood XIX and brood XIII for another over 200 years. I totally agree, this natural phenomenon is amazing. It's really short. I do know for a fact that there are scientists planning to throw parties where they're going to be eating cicadas. There's a lot of fun you can have with this as well.

Brigid Bergin: Well, let's take a moment and pause there on the eating of the cicadas. We've had several listeners text in with questions asking if you can eat them. My producer said there are some recipes that she's seen. I'm wondering, have you decided whether or not you're going to partake in eating any of these cicadas and do you have any advice for someone looking to find some cicadas to cook up?

Benji Jones: I have not, and I'm sorry. I wish I could say that I had. There is a very intelligent and skilled chef biologist, Martha Weiss, at Georgetown University, and I was speaking with her last night and she was telling me some of the ways that she prepares cicadas. One thing she said is that the entrée into eating cicadas is just to fry them up or dry roast them and then dip them in chocolate. If you do that, it tastes basically like a crunchy chocolate-covered pecan. These are her words, not mine. I have not tried this, but I would be very much interested in doing that.

Then also, she mentioned that you can do a teriyaki cicada, so cook them up with like your favorite spices, soy sauce, et cetera. She said this is more like a shrimp type taste and I think she even called it shrimp of the trees. There are actually a lot of ways that you can prepare it and a lot of recipes out there. If foraging is your thing and you're feeling a little adventurous, I recommend it. There's not harm that can come from it. It's protein-rich. A reminder, lots of people eat insects all over the world and this is just another example of that.

Brigid Bergin: I want to take another question from Judith in Highland Lakes, New Jersey. Judith, thanks for calling.

Judith: Hi, thanks for taking the call. If I heard correctly, you said that this emergence of two broods at the same time hasn't happened since 1803. Is there any theory or hypothesis about whether it happening now is related to climate change?

Benji Jones: That's an interesting question. The emergence that's happening now is not related to climate change. This was expected. What climate change is doing, however, is that because it's warming up the soil, and warm soil is one of the triggers for the cicadas to emerge, it's possibly making some of the broods that come out every 13 or 17 years, some of those cicadas might end up coming out earlier because they have a longer growing time because the soil is warm and they need warmth to grow.

Basically, some of the cicadas might become 'fully baked', as one scientist put it, early, and that means that they will come out before they might otherwise. They still seem to stick to this four-year cycle for some reason. It's not necessarily changing which years the broods are going to emerge just yet, but there are some micro changes that climate change is causing. Super interesting.

Brigid Bergin: It's super interesting. Just one thing, what is the lifespan of the cicada? Obviously, if we don't try to eat them or otherwise interrupt their lifespan.

Benji Jones: It's basically, if let's say it's a 17-year brood, which is one that's going to appear in Illinois, it'll live for 17 years and then basically die very quickly afterwards. The vast, vast majority of their lives is that window of time where they're underground. They're spending very little time on the surface, and then the babies are basically going straight from the trees when they're born, straight into the ground and that's where they're going to be for another 13 or 17 years. That's really their lifespan.

Brigid Bergin: That's great. We're going to have to leave it there for today. Benji, I want to read you one text that we got on-- the listener writes, "Is this guest a teacher? He has a gift for explaining the subject in a way that is easy to understand and sparks curiosity in this 46-year-old mom. So inspiring. Thank you for having him on to discuss this phenomenon." Thank you, Benji Jones. He's a senior environmental reporter at Vox. Benji, I'm so glad you could join us and talk about the cicadas. Maybe, could we play a little cicada sound just to say goodbye to Benji because how could we not get a little chirp?

Benji Jones: I love it.

Brigid Bergin: All right, let's hear it.

[cicadas buzzing]

Brigid Bergin: Benji, thanks for joining us.

Benji Jones: Thank you so much, a pleasure.

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