In deep summer, especially at dusk, you can hear the cicadas*—go to this Wikipedia article, and you can see/hear a short video for a reminder. I like that sound. For years and years and years (I returned to Tennessee in the mid-’70s), that’s been the “summer sound of home” to me. (Often the lightning bugs came out about the same time.**) You can tell that even just one bug can make a lot of noise (though, again, I find it comforting). Wikipedia tells us these are annual cicadas:
Annual cicadas are Cicadidae species that appear every summer. The life cycle of a so-called annual cicada typically spans 2 to 5 years; they are “annual” only in the sense that members of the species reappear annually. The name is used to distinguish them from periodical cicada species, which occur only in Eastern North America, are developmentally synchronized, and appear in great swarms every 13 or 17 years. All other cicadas from all other biogeographic regions produce annual broods, so the distinction is not made outside of North America.
There are about seventy species of the annual cicadas, and they occur almost everywhere in the United States. Oh, and in all the species—even the periodic ones—it’s the males who do the screeching. I’ll just leave that there for your consideration.
The greenish-brown cicadas I knew back in the day weren’t any trouble. They sang their comforting song (which had a rhythm to it), mated, laid eggs, and a new (but different) batch hatched the next summer and did the same thing. They mostly stayed away from us humans. Didn’t fly into your hair like crazy blind bugs. They were (are) … civilized. Sadly, I haven’t heard them in this yard in some years—probably because we have and encourage a large bird community.
But we’re in the middle of—shriek!—an outbreak of the thirteen-year variety of cicadas, what they call the periodic variety. (There is also a seventeen-year variety, remember.)
You wouldn’t think a thing—a freaking bug—with a maximum two-month lifespan could wreak so much havoc, right? Here’s what we’re dealing with, again from Wikipedia:
After mating, the female cuts slits into the bark of a twig where she deposits her eggs. Both male and female cicadas [the ones who just mated] die within a few weeks after emerging from the soil. Although they have mouthparts and are able to consume some plant liquids for nutrition, the amount eaten is very small and the insects have a natural adult lifespan of less than two months.
When the eggs hatch, the newly hatched nymphs drop to the ground and burrow. Cicadas live underground as nymphs for most of their lives at depths down to about 2.5 m (8 ft). Nymphs have strong front legs for digging and excavating chambers near to roots, where they feed on xylem sap. In the process, their bodies and interior of the burrow become coated in anal fluids. In wet habitats, larger species construct mud towers above ground to aerate their burrows. In the final nymphal instar, they construct an exit tunnel to the surface and emerge. They then moult (shed their skins) on a nearby plant for the last time, and emerge as adults. The exuviae or abandoned exoskeletons remain, still clinging to the bark of the tree.
Then they scream, all ’leventy-billion of them in your backyard, to attract a partner, mate with said partner, and the whole thing starts again for about a month until 2037.
Gerry’s been busy observing them. One thing? Our bird table isn’t very busy. Normally he has to stock it up every day, sometimes more than that. But the birds aren’t frequenting the bird table much since the cicadas have been here. I wonder if they don’t like the nasty things, which are too huge to be eaten by many of birds that eat here. This bird/bug issue is something I can’t find information on yet.
• • •
UPDATE: Now I have learned more.
I’ve learned that some birds are eating the bugs. Or eating pieces of them, after they croak midair and fall down into the lawn. We’ve seen a dove or two on the bird table; they are seed eaters and cicadas don’t interest them. But I’ve seen robins and others hopping through our lawn—our lawn guy, Daryel, uses a deep, four-inch mow, which makes a healthy lawn—poking their beaks down looking for bugs. And they’re there.
However, that’s not the whole story—and we don’t have complete answers yet. Read this:
Scientists know that bird populations boom about two years after a cicada emergence, and that they decline about two years after that. Does the bounty of food during an emergence year set off a chain of bird population booms and busts that lasts until the next emergence? Is the ecosystem impoverished for 13 or 17 years after a bounty of cicadas? Or do the cicadas, sucking juice from tree roots underground, do something to the trees a year or two before they emerge to reduce the number of seeds the trees produce, therefore lowering the bird population?
Koenig thinks it’s going to take more than Breeding Bird Survey data to find out. “One of the enduring mysteries of evolutionary biology is how we have gotten these 13 and 17 year cycles,” he says. Koenig suspects that cicada and bird populations mutually influence each other, but he hasn’t figured out an experiment that will tease out all the dynamics of the relationship yet.
Audubon also has some interesting thoughts on this:
In Costa Rican rainforests, researchers understand that tropical birds usually avoid areas where cicada noise is the loudest, which can drown out their own calls. … the numbers of [some] species appeared to ebb and flow in step with periodical cicada broods in their territory. … [In some cases] populations were smaller in cicada years compared to years without cicadas. Their numbers also appeared to spike the following year and then stabilize. The study also showed that [some birds] in an area increased sharply one to three years following a feast of cicadas, then declined after that, suggesting that populations swelled to meet the abundance of food, and then dwindled when not as many of their species survived during cicada off years.
Even more interestingly, it’s not just our bird table full of food that’s being ignored by the birds. The Smithsonian Magazine tells us that …
When broods surface, birds have easy access to billions of new, nutritious snacks. It makes sense, then, that they would stuff themselves with cicadas and neglect the caterpillars. … While birds were busy feasting on cicadas, caterpillar populations boomed, and individual caterpillars grew larger. In 2021, researchers counted twice as many caterpillars as they did in non-emergence years, and those caterpillars caused twice as much damage to oak leaves.
Whoa, right? It’s a mystery playing out right in our backyard, we can see it, and we know there are no clear answers yet. I’ll keep an eye on this story.
• • •
I haven’t really walked in the yard since the bugs got here around the eighth. But Gerry had mentioned the holes they came up out of and sure enough, they are everywhere. The flowerbed, which wraps three sides of our backyard, is just wall-to-wall cicada holes.
This is just a random photo taken on the edge of lawn meeting the flowerbed. See all the holes? See the brown exoskeletons, now empty? You can even see one dead emerged adult, a black mush of body attached to two wings.
This the outer shell they shed after they emerge from the ground.
Walk through the yard, but watch where you put your feet. They’re everywhere. I don’t know that we can tell male from female.
There are two in this photo, too, if you look carefully.
I do wonder if there are cicada holes in the lawn, too, and we just can’t see them. I ask this because I have a clear view of the dogwood tree outside my office window, and have seen the egg-laying process (meaning, have seen a cicada stop on a branch and remain in that position for about thirty minutes). I can look out there any time and see both flying activity and nonmoving activity. So when those eggs hatch, the nymphs will fall either to … the lawn, the decorative pebble-covered flowerbed, or even a bit of the driveway. I’ve read they are strong diggers, so maybe they will dig down through the grass, maybe even through the decorative stones. I do wonder.
I’ve lived through this thirteen-year event three times here in Tennessee 1998, 2011, and 2024. In the ’90s I was working in the Crystal Terrace Building on West End Avenue in Nashville. My office had a large window that fronted on West End, and for about two weeks the cicadas flew into it by the hundreds. Over and over. They had a parking garage, so no bugs there, but if you went out to lunch—look out. By the time they came around in 2011, Gerry and I had bought this house. I think I mostly just stayed inside that summer. I do have a photo of Bean in the foyer, lying down next to the bug she’d caught and brought in through the cat door. Thank God Henny hasn’t caught one yet.
We are all ready to see the back of the bugs. Not just Gerry and I, but everyone here in Middle Tennessee. It’s all we talk about. But the thing is … this is really just a circle of life thing, you know? Check out this article from In Defense of Plants on May 8, 2024:
Brood XIX is emerging after 13 years of living underground, sucking sap from the roots of trees and other plants. This brood consists of 4 different species of cicada and the synchrony of their emergence is truly spectacular. I hope you realize just how fortunate you are if you live in an area where you get to experience it. I see far too many posts from ignorant folks asking how to get rid of them or complaining that they are too noisy or people talking about cooking and eating them. More than anything, I think insects like this need to be left alone, to do what they do naturally, because they only have a few short weeks to pull it off. The whole goal with this mass emergence is to swamp their predators and get down to the business of mating and ushering the next generation that will slowly mature underground over the next 13 years.
The impacts of this emergence will benefit the entire ecosystem. The soil is aerated as the cicada nymphs burrow up to the surface, allowing a mixing of water and air that is crucial for soil health, countless birds, mammals, fish, and more will benefit from such an abundance of protein- and fat-rich food, no doubt having boom years of their own after this. The trees themselves will be pruned a bit as the female cicadas drill into stems to lay their eggs, but research shows that trees like oaks often experience banner crops in the years following cicada emergence. Moreover, the nutrients that will be returned to the soil as the cicadas die off over the next few weeks is a huge boost to plant productivity that doesn’t always happen during normal years.
All told, Brood XIX and other periodical cicada emergence events are so much more than just an annoyance, a trendy meal, or even a spectacle for content-needy folks like myself. They are an absolute boon to the ecosystems that supported them for 13 years and hopefully for millennia to come. So, for the love of nature, please let these wonderful insects live out their last few weeks screaming for a mate and getting down to business. Appreciate it for what it is as it will all be over before we know it.
OK, OK, the “I hope you realize just how fortunate you are if you live in an area where you get to experience it” is a bridge too far for me, but I did learn something here. And no, no, you don’t need to be out there trying to kill them. Don’t do that. Read that middle paragraph, and be enlightened. The bugs have a purpose, it’s a good one, and we should amend our attitudes.
NOTES:
* I’ve been pronouncing this sicAYduh for years, but I’ve noticed lots of folks saying sicAHduh. So I just looked it up out of curiosity. (I’m right—it’s sicAYduh!) Back in the ’70s we called them locusts, but while that word is still sometimes used, it’s not accurate for the bugs we’re discussing here.
** The US Fish and Wildlife Service recently published a little article that began “Where did all the fireflies glow?” It goes on, “We get asked the question all the time—hey, why don’t I see that many lightning bugs anymore? The simple answer is, maybe your community is no longer a good habitat for them.” Here’s a longer article I’d urge you to read.
Wanderlustful 