Once again, as it has been now for several summers, I am sitting on my deck near dusk casting careful glances across the yard. I am on a mission. It has been one of those steamy summer days, and screaming cicadas in the treetops are providing an acoustical curtain call to the day, ushering in nightfall. Cicadas you say? You may not think you know this insect, but you really do. You may not know it by sight, but certainly you have heard its loud, pulsating buzz.
It is late summer here in the Midwest, often a time of sweltering days, clapping thunderstorms, picnics and plenty of bugs.
Earlier today the cicadas (pronounced si-KAY-das and sometimes mistakenly called locust) screamed louder than usual, urged on, I am sure, by a stifling humidity. Little else stirs in the yard when summer days are like this.
But it is stirrings in the yard I am looking for this evening as I have done for a couple of weeks now. My attention focuses on two very large silver maples. My curious habit of late is watching catbirds walk across the lawn, stealthily silent in their movements as they approach the exposed roots of the old, twisted maples. I know their quarry and purpose. Their dusk strolls are well timed. For it is precisely this time of the day at this time of the year that big, fully grown cicada nymphs tunnel up to the ground surface, crawl up the tree trunks, split their crusty skins and become winged adults.
No one really knows for sure how a cicada nymph measures time and decides the fateful moment of pushing itself out of the earth, but it is surely a marvel of nature’s precision. Possibly soil heating up as summer moves along signals the waiting nymph to ready itself for that punch through the ground. Something else then guides the cicada to wait for dusk, with the final molt taking place in night’s cool protection. It is a necessary but risky transition for a creature that spends most of its life, spanning years, underground, surviving, if it does, to be a true sunshine aficionado whose life above ground lasts only a few weeks.
Believe me, this plump juicy cicada nymph, about the thickness of a man’s thumb, is filet mignon to a catbird. And catbirds are successful with their hunts in my yard. This seasoned neighborhood, with its old stands of maples, ash, white oaks and a few surviving elms, is fertile territory for cicadas and their poachers.
Old, big trees breed lots of cicadas, but a cicada’s life is always a very tenuous matter. Many fall victim not only to the sneaky catbird, but also to other birds, raccoons, field mice and perhaps squirrels. And people kill cicadas out of misguided fear, an instinctive, swift, crush underfoot of a freshly exposed nymph that strays onto a driveway or sidewalk. Nonetheless, by summer’s wane my yard is littered with their castoff brownish cast “skins.” Sometimes I even find several clinging to a nearby wooden fence.
Cicadas you see, can be just as much a part of a yard’s natural history as butterflies, crickets, katydids, wasps and mosquitoes.
While there are various kinds of cicadas, I speak here of one kind, the annual cicada, known to science as Tibicen. This big creature, with its black-and-green-mottled body, large green eyes, powdery white belly and crystal clear wings, is the one that’s around every year, late July through early autumn. Even though it takes years for Tibicen to mature, adults appear every summer, a consequence of staggered generations and different rates of growth.
You must agree that you have to think very hard to recall the last time you laid eyes on an annual cicada. It’s one thing to spot the stout, brownish husks clinging to tree trunks, ghost-like and eerie with bulging eyes and digging front legs, but try spotting an adult. Mostly we find a cicada only when one falls out of a tree, blown down by a gust of wind or strong rain.
I must tell you that even in neighborhood yards and city parks, cicadas are interconnected with the rest of the fragmented nature in our midst. You see, tree-lined streets and small pockets of woods in parks give a sense of permanence to cities and suburbs, and attract interesting wildlife. Trees and little woods are amazingly at home in people-populated places. And this is good for people, nourishing the intellect and spirit, giving some closeness to nature. Every creature, including the cicada, is a part of this persistence of nature, embodied in a history far older than the human presence. The cicada helps us sense nature’s permanence, and complete the summer season.
Could you even imagine an August or September day here in the Midwest without cicada music? Cicadas bear witness to weddings, barbecues, canoeing and baseball. We bury loved ones within earshot as they call from cemetery shade trees. Family porch chats at dusk slip into inky darkness as katydid and cricket serenades take over where balladeering cicadas leave off. When you spend some time with me here on the deck, be it at high noon or dusk, you, too, will begin to sense that this seldom-seen but surely heard exquisite creature gives us a new perspective on summer.
There is a bold lesson here. The cicada is a fine-tuned being, clocking off the ticking of summer slipping toward yet another autumn. And its appearance occurs via a genetic code engraved over thousands of years, uniting two worlds, one below ground, one in the sunshine. The life of a cicada bridges the tops and bottoms of shade trees, branches, roots and all in between that sustain a big tree. There are no shortcuts to the cicada’s well-being and its role in nature.
In both worlds, in darkness and light, the cicada plays out a specific ecological destiny. Cicada nymphs churn up the soil, breathing fresh life into it, promoting the well-being of a whole suite of soil creatures, including bacteria, fungi, mites and ants. Certainly beneath ground the nymphs are prey for moles and other burrowing animals. Their cast skins litter the soil and mulch, creating minute pockets of sugar that enrich the soil for other life. And while nymphs are part of the soil system for years at a time, the elusive, winged adult phases in and out quickly in the above-ground landscape, embellishing it with a brief but vibrant presence in late summer each year.
Cicadas and trees, then, are like intertwined, synchronized clocks. Cicadas are tied to woodland and planted shade trees whose own annual rhythms also follow the march of the seasons.
So for more than one reason, finding cicadas in my yard is anything but happenstance. It is a matter of history, human and natural.
The annual cicada was, and still is, part of the complex webwork of creatures that makes up a healthy forest. Early settlers cleared much of the forest and planted shade trees–oaks, maples and others–to line their dirt streets, antecedents of a future-paved Main Street, Michigan Avenue or Lake Shore Drive. Cicadas, katydids, robins, blue jays, orioles, catbirds, squirrels, field mice, wasps, wild silk moths and other forest creatures moved into these planted trees. All of this happened as villages and towns expanded and aged, becoming cities, pushing aside more and more countryside and forests. And back then, like today, the cicada’s presence in these places, as well as in scattered remnant woods on farmlands, reminded people of the broader scheme of nature. Often dubbed the “dog-days harvest fly” by early settlers, the annual cicada’s call ushered in the harvest. You see, when trees endure, cicadas, birds and other life also endure, coaxing us to bear witness to the seasonal personality of this land.
Some would argue that the cicada’s pulsing whistle-buzz is anything but appealing to the human ear. But I sense something deeper in the sound. This too is a matter of timing. One’s personal fondness or annoyance with cicada music has much to do with the ways these beasts structure their recitals. Sometimes an individual cicada sings, followed by another in a neighboring tree, as if the two were harmonizing back and forth. At other times, several others chime in when one starts up. The air becomes electrified with a mounting cadence, a pounding shrill. What had been a solo performance or duet jumps way up the music scale into a full-blown concert, hardly difficult not to notice, like it or not. Such fiercely energetic activity speaks of the ribalda frenetic preoccupation with procreation. Summer means courtship and sowing seeds for future generations of life.
Summer’s own path–its inception, blossoming and decline–guides this fate of nature. As little as a month ago, my yard was silent of cicadas. Now the place is a cacophony of insect serenades. And three months from now silence will again ring through this yard.
But what is going on in the treetops above us right now helps to ensure summers yet to come being filled again with cicadas, and more opportunity for marauding catbirds, mice and nerve-stunning wasps. But a lot of things can happen between the time that a female cicada is lured by the male’s call, mates, then carefully places her tiny fertilized eggs in slits she fashions in tree branches, and when a nymph finally digs its way skyward out of the earth many seasons later. It takes anywhere from seven to nine years for an annual cicada to grow up.
The cicada has a challenge: to survive in people-changed landscapes–towns and cities–where nature is compressed, packed in, measured to some degree by the placement and numbers of shade trees.
Birds aptly chase after cicadas in treetops, cued into singing males through dense foliage. Birds are very good listeners. Sometimes I hear a loud squawk high above in a tree. Locked in the beak of bird, a cicada is thrashing aboutand squawking. And did you know that a certain fly locates a singing cicada and lays its eggs on the cicada’s body? Its young hatch out, burrow in and feed. The wasp known as the “cicada killer” provisions its earthen burrows with cicadas immobilized by its powerful sting, and then lays an egg on each captive host–a tasty and complete food supply for wasp grubs.
All is not grim in this backyard scenario. I also know that tucked away in those high branches of silver maple are cicada eggs, placed there by the few who have made it long enough to breed.
In a few weeks, the eggs will hatch–if they are not discovered by ants–the baby nymphs, hardly bigger than the average ant, dropping to the ground and digging in deep for a long time. So you can appreciate that a tree, from its lofty crown to its deep roots, is pivotal to a cicada’s existence.
Cicadas in treetops use a tube-like, sturdy mouth to tap into branches and suck up sap. Their nymphs tap tree roots in the same way. Sap, a tree’s blood, is a watery broth of sugar, protein, fat and minerals, foodstuffs that provide the energy, strength and endurance cicadas need to drive their powerful muscles.
And cicadas use a lot of energy. The male makes its boisterous song by rapidly vibrating its stomach muscles, causing a pair of stretched drums to move; this creates a pulsing sound amplified many times over by the largely hollow body cavity. The fine structure of the drums and the beating rhythm of the strong muscles give each type of cicada its own unique song. And rightly so; this avoids confusion during mating in places where one species overlaps with others. Females have no drums; their body cavities are designed to hold hundreds of eggs, fertilized when cicadas copulate in silence in treetops.
The personality of the cicada’s song is shaped by weather one moment to the next. Cicadas sing loudest when it is hot and humid. A sudden change, such as a shift in the winds off a lake, drops the air temperature, shutting them down in an instant.
As we look out at this yard of mine, comfortable as we are on the deck near nightfall, we have every right to be concerned about what goes on with cicadas (and other wildlife for that matter) in the trees, beneath the ground and on it. And I hope you will agree with me that the cicada and its “dog-days” theatrics reflect the essence of the Midwest summer. It should be easy for people to think about nature when the landscape is dense with foliage and bug activity. But I will wager you that even in summer, people seldom think about what is happening with nature above and beneath the ground, with the exception of gardens and lawns. Don’t you think that the cicada and its curious life help to close this gap in our collective awareness of nature? I hope you do.
A lot can happen to a stand of trees in the string of years it takes for a cicada to grow up, burst out of its shell and fly away. And much of what happens is not good at all. I am not referring to the natural enemies of cicadas. Such interconnections are part of a natural design. I speak of another danger, one not in balance with nature. In fact, it often short-circuits the vision of our forebears that having shade trees is a good thing for people and the rest of nature.
I know that I will keep my silver maples for as long as I live here. But what happens when people cut down their trees for whatever reason, or when diseases, encouraged by alteration of the landscape by humans, kill off trees around us? I can tell you one thing for sure. What was once a little woods, a quaint tree-lined street or field dotted with shade trees can become a parking lot, supermarket, shopping mall or highway spur. Then cicadas die by the thousands. Other life dies too. Katydids, songbirds, silk moths and much more will continue to vanish from our neighborhoods. Especially in cities and towns, nature needs a certain critical mass in order to survive.
Is the cicada’s seemingly desperate call not only a warning of summer’s passage, but one of interdependence of humans, wildlife and trees? When the big trees go and humans don’t reseed the landscape, the cicada’s song also surely will go. Losing cicadas is not a trivial matter. It is both a real and symbolic breakage of the interconnections that make our summer whole, and that which we surely want it to be for future generations. Networks of many small creatures provide pillars of support for the more obvious faces of nature–woods, wetlands and other wild, sacred places. So we cannot afford to forget the cicada and its summer message.
If we give more thought to trees, birds, cicadas and neighborhoods, can we begin to understand the interconnections? A cicada is recycled, reworked plant juices. Catbirds are largely the reworked flesh of cicadas and other insects. So, too, the cicada killer wasp. Shade trees are hosts for cicadas and other insects, as well as nesting and food-hunting grounds for many birds. Soil and mulch shelter many tiny creatures, many of which feed shade trees. And from here, the interconnections among creatures branch out even more. But I hope you are beginning to see the picture, to sense nature’s design and complexity, even in my yard in summer. It is a good thing to spot catbirds stalking cicada nymphs at dusk in this place, for seeing such things tells me that nature still thrives here.
So let us listen to the cicadas’ and crickets’ summer evening serenades. And let this acoustical continuity between day and night remind us that we are all the keepers of nature’s presence.
Soon enough, autumn’s chill will muffle the music of cicadas and crickets for another year. But think ahead to next summer’s sounds and those of summers yet to be. Think, too, of the magic cicadas bring us, reminders of where we came from, embellishments and insights about this present life, steering us wisely into the future with a freshened respect and awareness of nature’s permanence, close at hand.
