Swarm Behavior | Paulina Jenney

42 mins read

Acronicta leporina

It’s late April in Bisbee and the sun is in the wrong place over the Swisshelm mountains for the kind of hot it is. The perry penstemons in the yard have already flowered and dropped their leaves, and today while driving the ranch road up the wash, my skin started to crisp before my watch struck noon. Not one month into spring and my dad has already filled the old concrete water tank behind the shop into a makeshift swimming pool. When I went to jump in, to cool my sunburned skin, I pulled back the tarp to find a swarm of bees, the top few inches of water muggy and tepid. In any other year, this would just be your run-of-the-mill too-hot-and-hotter-every-year, twenty-first century spring. This year is different. Different because of the moths.

I had gotten down to the ranch the week before, after a long day’s drive from the mountains in Flagstaff. I was eager to get back to the tiny house project I’d been working on before I’d left the country, to sit under the twinkle lights on my dad’s porch across the property, to stay up late and drink beer and listen to old Chris Isaak records in the soft desert nighttime breeze. I was eager to be in a place where we could hole up, tune out, to be alone, far away from the cities where humans were killing each other through the sheer density of shared airspace and a virus that would not stop replicating. Out here, in Cochise County, Arizona, there were less than ten people within a mile’s radius. No vectors of infection to be seen.

I turned onto the road well after dark, cobbles crunching under the tires the only signal that I had made it home in the vast nowhereness of the borderlands. The headlights flashed against the glass door on the small trailer, and I parked the car, pulled my duffel out of the back seat. I cranked open the doorknob to my half-finished house, dusty from a year of disuse, and walked into a face full of fluttering, heavy insects—jumped back and further stirred up the black, dusty, winged cloud, feeling their wingbeats thick and frantic in the darkness. I swatted my arms instinctively in front of my face. When at last I thrust my hand past the door and flipped the light switch, ten thousand moths stirred from every corner of the house—from the walls, the windowsills, the storage shelf over the bathroom.

Holy shit. I slammed the door shut and sent a message to my dad. “Here. My house is full of moths though?” I wrote, not knowing how else to put it.  A few minutes later, a flashlight appeared bobbing in the distance and my dad came walking up with a Shop-Vac and a fly swatter, like some sort of Moth Buster, as if his gear had been waiting by the door.

“Oh, it’s just insane, isn’t it?” he asked. “These things have totally taken over. You should see my place.” He plugged in the vacuum and started sucking the moths off the walls.

Picture, for a moment, my dad: silver hair and 70’s-style glasses glinting in the moonlight, head to toe in denim and a black felt cowboy hat, vacuuming up a thousand moths one at a time fifteen miles in the middle of the desert. Our own plague, the book of Revelation gone western: a swarm of moths.  If it weren’t so lonely, so late, it would have been absurd.

Army cutworms, commonly known as miller moths post-metamorphosis, are an unusual species of moth in that they hatch as worms in the late fall, feasting on winter crops like wheat and root vegetables before burrowing underground. In the spring, they wake up, emerge from the soil, eat some more, and begin to fly, following the flowers into the mountains. They leave behind a sticky excrement, but they don’t chew clothes, bite, sting, or smell.  Although the moths can wreak havoc as worms, they’re virtually harmless in their winged form, unless you like to read in bed and don’t like being dive bombed in the face, or if the sound of small bodies hitting the wall behind your head keeps you awake when all else has gone silent for the night. 

I found this information on an agricultural resource page out of Nebraska as we drank coffee in my dad’s kitchen the next morning, after I asked him what was going on.

“I don’t know,” he said. “They just showed up one day,” an old cowboy bewildered, but not surprised by the wildlife making home in his rafters.

The page was written for farmers in the fall, warning them to protect their crops from pests. Beware the “armyworm” habit, it said, after all the vegetation has been consumed. The worms will band together and crawl across fields and towns, ravenous in the quest to consume what they can before winter comes. There were tips for mitigating the worms in fields, and even how to seal your house against the moth invasion in the spring. 

But we are not in Nebraska. We’re in southeastern Arizona, far from residential areas, agriculture, and even perennial water. No one can say for certain that the moths are supposed to be here. 

Every morning, we drink coffee on the front porch of the house before standing up, brushing off our jeans and getting to work for the day. I cut drywall, mud joints, wipe my sleeve across my face as the sweat beads on my forehead. I cut a hole in the side of my trailer with a saw and install a swamp cooler, which has to be filled with five-gallon buckets from the well every few hours. I spray insulating foam into every needle of light I can find, hoping to seal it from the moths and the outside world. 

Still, every night, thousands of moths somehow wiggle their way into the houses, even if the doors have been kept shut and the lights off. They coat the screens of the windows and any inch of wall that’s mildly illuminated, including the glow of a nightlight or even the reflection of the moon against a white wall. As the evening grows dark, the moths grow thick. Then, at some point between the hour we have blearily hauled ourselves to bed and the time the sun comes crawling up the back side of the mountains, they’re gone. 

For the next few weeks, I learn to whirl a small towel over my head like a lasso, stirring the air in the house and rousting them out of their hiding spots before bed. I move all the lights in my house to the front yard, trying to create an artificial moon too tantalizing to turn away from. I want them to live, but I want them out here, in their own space. I dance out in the yard with the doors open until it seems as though most of them have joined me, then pull the door almost shut, suck in my breath, and slip back through the crack. I bat at the stragglers with a flyswatter or a broom. 

For a minute, I can feel their tiny racing heartbeats in mine, their desperate swerves and jumps in the last few moments before death. I feel their panic and I empathize, confused, the world a bright prison with flat walls and sharp corners. For a minute, I consider letting the moths live. Is it their fault they have chosen this moment to expand while the rest of us fold into our cocoons? But what am I to do? I have to sleep. I kill the moths and it breaks my heart. I read the news and it steels it. I turn in another day. The sun melts over the mountains. The moon comes out, bright, hot, enticing.

It isn’t until late in the summer that I wonder about the moths again, and this time the reports from agricultural extensions across the West are in, concluding that in addition to an economic crisis of catastrophic proportion and pestilence beyond any pandemic in modern history, this spring saw a plague of miller moths that confounded gardeners and farmers across the country. Typically, they hatch in the High Plains and migrate west, and because of an extremely dry year in Nebraska and Kansas, and Colorado, the moths that would normally spread out in all varieties of flowering plants were concentrated into irrigated fields. There, they turned into swarms that flew west together, coating any community where there were blooms or water or both before moving on. In the desert, the water cisterns behind the house were full, thanks to late fall rains and a wet winter. It was hot, too hot, but the ocotillo blossoms bloomed, offered up to the sky on twiggy branches like torches lighting the way across the desert. The moths touched down on our ranch because we had something few other places did in those early April days. They stayed, both they and we appreciating the same gift of a fluorescent desert.  

When fall arrives and the desert finally cools, my great aunt, who is ninety-three and lives in Oregon, comes through with her daughter on their annual migration to Mexico. We sweep the moth bodies like nutshells off the big table that has gone so long unused this year. We sit outside, where the wind moves our breath out and across the land. We eat dinner together and talk about how we are all just looking for company and somewhere sweet to stop on our strange and often lonely journey across the wilds.


Apis mellifera

Remember the bees, buzzing under the plastic covering the surface of the water tank? In mid-summer, they are still here, and now thirstier than ever.  

When he’s finished with the workday, my dad pulls the plastic back sinks into the small homemade swimming pool just big enough to dunk under. The bees continue to sip and commune in their half of the pool until dusk approaches and the first lights across the border begin to blink on down the valley.  He stretches his arms across the other edge of this, the only source of water for miles. He floats and lets the warm blanket of the high-pressure air settle around him, silent except for the incessant drone of the bees.

“Boys,” he’ll sigh, “you’ve been at it for hours. Take the rest of the day off.” In fact, all worker bees are female, but who is going to correct him? They have a rapport, my dad and the bees, both appreciative of the way the ocotillo blooms lasted an extra couple weeks this year and both devoted to the sticky, slow, gold that results from their labor. It never occurs to my dad not to share his pool with them, and I, too, float small twigs across its surface in order to give them a place to sit and drink without wetting their wings. In the desert, you never begrudge a living thing a drink of water.

“Did you hear about Dan Oldfield?” my brother texts me one day when I am away. “No,” I reply. “What happened?” I think about the last time I heard anything about Dan Oldfield, our closest neighbor out there in the middle of nowhere. I imagine his rattly lungs and the pandemic sweeping through our state and fear the worst.

“He hit a beehive at his place today and the bees killed him.” The bees killed him, my brother said, as though those sweet sippers of tepid water had banded together and plotted Dan’s murder. He was driving across his property, clearing brush on a tractor, as my dad often does, and he ran over their hive. They swarmed the giant, roaring monster that crushed their home, found the heart of the thing that lives and breathes and beats, and they went after it. Later, we will hear about how he must have run for cover, made it into the tool shed near his house, but the bees found him there, and the bees did what bees do.

The bees killed him. I turn the story over and over in my mind until it’s no longer Dan I’m talking about, but an ecological enigma that sounds so incredibly strange when I say it out loud. Put it this way, the bees are the subject of the sentence, the swarm a sovereign arbiter of Dan’s fate. It’s not that he was stung to death by bees. The bees did it. The bees killed him. At night, I read articles about deadly bee attacks, learn by heart all the ways a swarm of insects can take down a human being. 

According to experts, all the wild bees in Arizona are Africanized. “Africanized” here means that the bees are a cross between the European honeybee, which is better at storing honey, and the East African lowland honeybee, which is better at storing pollen. These hybrids also tend to colonize and swarm at higher rates than the European bees and are more aggressive when defending their home. In 1998, in downtown Bisbee, someone sprayed the hive that had been there for as long as anyone could remember, igniting a swarm that roved the streets, terrorizing residents. Police officers ran frantic down Main Street with blankets over their heads. Cars swerved around each other, narrowly avoiding collision. The bees stung everything in their path, including dogs, streetlights, bicycle tires. Eight people landed in the local hospital which, coincidentally, has exactly eight beds. In Arizona, there is about one deadly bee attack a year, and every single one is a complete surprise. 

In 2006, when a man was fatally swarmed by a quarter of a million bees that had taken up residence under his house, the exterminators called to remove the hive said that prior to the attack, “They weren’t bothering anyone.” In the desert, we are grateful to be alive in a place so rugged and inhospitable, and we share a camaraderie with everything else trying to survive under this infernal sun. We scoop the rattlesnakes off the inverter when we need to turn the power on, and we step around the agave growing into the trail. When the coyotes howl into the night, the hound that sleeps on the porch stands up and howls with them. 

That week, I couldn’t stop talking about it. I had taken a job on a construction crew in Flagstaff, and we were remodeling a second home in the mountains, tearing out walls, staining cedar planks, building a geometric staircase for a couple from Phoenix who were hoping to migrate out of the city and into a place with a little more peace and quiet. Their friends had come up first, and then other friends bought the house next door, and on and on until they owned every house on the street that overlooked the golf course. “Oh, we love coming up here when it gets hot,” the home buyers said. “So many people down there in the city, you know. So busy.”

“The bees killed him,” I said to the crew.  “But they’re not sure how. Sometimes a swarm can choke a person to death. They crawl inside your nose and mouth, looking for weaknesses, and you can asphyxiate on all those wings…” I paused, waiting for a reaction. “It’s also possible that he had a heart attack running from them. It takes a thousand stings to kill a grown human being.” 

Vince shook his head as he swept the sawdust off the floor. “You never know how you might go,” he sighed. Of course, an awareness of our impending demise and our inability to predict how and when it might happen are defining hallmarks of the human condition. But how nonsensical is it all? How you can be seventy years old with a heart condition, gripped by the exponential replication of a virus, and be murdered by a swarm of bees? Did Dan wake up and listen to the news? Wash his hands an extra time? Stand back when the mailman pulled up to chat? In the face of unfathomable risk, we strive to create a sense of safety for ourselves. We do what we can to survive. But how just how far can the self-preservation go? And maybe it’s all futile anyway, to look after yourself in such a way when you’ll never be able to foresee it all. 

It could have just as easily been my dad, who drives his Bobcat with the door taken off, dozing over acres and acres of catclaw in an attempt to restore the grass that once blanketed that corner of the valley. When I call him later, to remind him to put the door back on the tractor, he assures me that he’s spoken with his bees. “Now,” he said to them when he sunk into his pool that afternoon, this time the air a different kind of quiet, “you boys better not have had anything to do with this.” 

These bees, he rationalizes, are his friends. They have a rapport. Those other bees, well.


Swarm behavior

When news first broke that actual murder hornets had arrived at our shores from the far reaches of east Asia, in January 2020, it didn’t take long for us to start briefing our bees on strategies for victory. “Listen up, bees,” one article read, “even though you’re outsized, you can still win this. We learned this one from the Japanese bees, who are used to fighting these things. The trick is to lure the hornet inside your nest and act as though nothing is amiss. Then, on cue, you swarm the enemy, form a tight ball around it, and buzz, you know, do your thing. The vibrations from your little bodies can raise the temperature inside the swarm to over a hundred and fifteen degrees. The hornets can’t survive a heat like that.” The bees, of course, can and do.

In “Ecologies of Empire,” Jake Kosek explores how bees have both shaped and been shaped by US foreign policy, proposing a framework of “political entomology” that documents the military’s use of bees as models for defense operations. Bees become bomb detectives and intelligence officers. They monitor sites of nuclear fallout, because radionuclides in plants are taken up by bees and are evident in the honey they make. Scientists train them, several at a time, in a Pavlovian process, to stick out their tongues at the smell of landmine. 

In addition to training bees to the call of duty, the Department of Defense has also modeled their training of humans after the behavior of the buzzing arthropods. When bees swarm, they demonstrate mobility, flexibility, adaptability—highly desirable traits in wartime operations. They are able to execute missions with no central decision maker and no preordained pattern of attack, making them difficult to control. The goal of swarming “is to overwhelm any cohesive defenses that might be mustered,” writes John Arquilla, a military advisor and the author of “Swarming and the Future of Conflict.” The same tactics, he reasons, could be applied in military theater.

But swarm behavior isn’t only combat, of course. Kosek also writes about the gentleness of swarms. After strong cold fronts, dragonflies, which are usually solitary, migrate in bunches to keep their heading against the wind. A flock of starlings becomes a murmuration, forming an undulating mass of up to a million birds to alight at a roosting site that keeps them warm at night. When roosted, starlings can pack themselves into hedges at a rate of 500 birds per square meter. 

And how do they do this without crashing into one another? Until the 1930’s, scientists thought it must be magic, a form of telepathic communication. Now, models show a single starling observing the seven closest birds and matching their speed and direction until the entire flock appears to be one unified, swooping, spiraling being.  When bees migrate for food and shelter, a bee with information does what’s called a waggle dance, where she vibrates her body at the angle of a nesting site or food source. When enough bees have the message, the entire swarm moves in a coordinated direction. By watching each other and trusting their instincts, the bees form their hive mind.  

Still, this swarm intelligence has been appropriated by everyone from Donald Rumsfeld to data scientists in order to try to optimize humans’ tactics in competition. What we take from the swarm is how to become a team, and in our world, a team is nothing without an opponent or a problem to tackle. So what makes a swarm a swarm?  Is it only insects that can do it naturally? Can a virus swarm, as it proliferates uncontrollably across a landscape? Can humans? 

A single grasshopper becomes a locust when there is plentiful food and moisture and his territory becomes crowded. The more crowded the space, the more social the grasshoppers become, until they form a swarm that roves across a landscape, devouring everything in its path. This year, locusts swarmed across large swaths of East Africa and the Middle East, the worst plague of locusts in almost a century. A locust swarm the size of one square kilometer, the FAO reports, can eat the same amount of food as 35,000 people. In Kenya, one swarm was reported to be over 2400 square kilometers, a swarm that could coat New York City three times over. In a year where it seems everything is multiplying beyond control, perhaps the locusts have outdone them all.


Lasius niger

I was nine or ten years old, standing with my friend Gracie at the bus stop outside Marshall Elementary School on a day when the sun was shining and the grass at our feet was tall and overgrown. We were standing at the bus stop chatting, our plaid uniform skirts swishing around our knees, when the tickle of the grass around my calves became particularly intense. I looked down, to step away from the offending flora, and realized that my leg had been transformed into a writhing black mass of ants, and that I had been perched, like a giant pillar, on top of the entrance to their colony.

I lost myself in the stomping and shrieking and shaking and jumping around, and I don’t remember the bus ride home or what we had for snacks when we got there. For days, I could feel the skin on my calf liquify and move.  Still, to this day, people look at me sideways and say, “Ants? Really? But they’re so small and harmless.” 

“Militaristic little fuckers,” I’ve said, even before I knew about the Department of Defense and their bees. “They can take down an enemy a million times their size, with nothing but orders from the great unheard shot caller, their own collective consciousness. No thanks. I prefer crawlies that think for themselves.” Isn’t our psychological solitude, the fact that we are always internally alone, what makes us what we are? It’s always amazed me that everyone knows the word for arachnophobia, but nearly none have heard of myrmecophobia. I have no problem relating to spiders.

But perhaps what I’m feeling isn’t fear of ants but fierce jealousy—which in itself is a type of fear—of inferiority. Humans have positioned ourselves at the top of the food chain, granting our species dominion over all others, justified because we have declared ourselves to be the most evolved. But here are all these insects and their miraculous swarming habits, their efficient decisions, their cooperation, their ability to provide food and shelter and to take care of each other. How nice it must be to be a part of such a cohesive whole. The ants don’t wrestle with self-preservation, the daily torture of where to go or what to do to ensure the best possible outcome for themselves. They watch the ants around them and do what they do; they prioritize the behavior of the whole.

Maybe what I’m trying to say is that the ants, the bees, the moths have turned a mirror back at us, showing humans our true ineptitude when it comes to getting along in crowded spaces.

Early human groups would have been small bands of people no bigger than your family or your group of friends. Population density on Earth, at the time of speciation for Homo sapiens roughly 200,000 years ago, was about one person per 200 square miles of land. In the year 1 C.E., seventy-five percent of the world’s population lived in Asia, and the density almost doubled to one person per 111 square miles. Today, only 2020 years later, humans have reached an average population density of about 129 people per square mile, and in places like New York, there can be upwards of 1,000 people per city block. And how do we go about coexisting, with all of those people in close proximity? We plug in our headphones and keep to ourselves, and when we can’t do that, we yell and shout and swerve and shut down. We argue incessantly about the best course of action, and when it comes to making sacrifices for the benefit of all, we drag our feet and do what we want. We’re so new to this type of living that we make ourselves sick. When it comes to efficient swarm behavior, insects have a 120-million-year head start. 

Do not misunderstand: this isn’t about overpopulation. It’s certainly not an attempt to diagnose What’s Wrong With Us. Sure, there’s plenty wrong, but I offer something other than an admonition: it’s an observation, an explanation that sees past our clumsy behavior. We just haven’t figured it out yet. In deep time, we’re a nascent species. We’re under-evolved. 

For most of human history, our success has been our autonomy, our sense of self, our ability to remember where the best food is or where we could find shelter. The fact that we have personal memories means that we can want things we once knew. We can contemplate our own death and make conscious decisions to avoid it, no matter how futile those may or may not turn out to be. But perhaps the planet is sending us a message, pushing us toward pods and hives and flocks and swarms.

The evolution will not be cultural. It will be biological, instinctual, as humans crowd together in denser and denser spaces. We will watch out of the corner of our eyes, adjust our speed to those around us. We will come to know that the success of the individual depends on the coordination of the whole, and we will rise to the challenge, growing the parts of our brains that understand each other without speaking. We will buzz, murmur, emerge something else, something better.


Magicicada septendecim

My dad sits on the balcony of his house in the evening, drinking his ritual glass-bottle Coors Light and looking out over the ocotillos he’s just transplanted into his still-imaginary courtyard. Other than a smattering of tract houses from a forgotten subdivision down the road, he’s the only human in the desert for miles. It’s been almost a year since Dan died. The cisterns behind the house have all run dry. 

He’s started running water out to his trees in buckets, and the wildflowers that were so prolific this time last year are nowhere to be seen. The Shop-Vac gathers dust in a corner of the garage. When the moon comes up, the house is quiet. 

“No moths this year,” he says to me on the phone. “I guess that’s the thing with these epidemics, pandemic, whatever they are. It’s just one damn thing after another. Who knows? Maybe this year it will be grasshoppers.” 

I think about the cicadas brewing under the eastern half of the country, where so much life is already amassed. The swarm spends seventeen years underground feasting on the sap of tree roots and emerges, as if on cue, once every seventeen years. The brood, dubbed Brood X, is set to emerge this spring in 15 states, from Indiana to Washington D.C. at a rate of 1.5 million cicadas per square acre. The cicadas will live above ground for a few weeks to fly, mate, and lay their eggs. By midsummer, they will be gone, having satiated the birds, leaving their carcasses to fertilize the forest floor. The last emergence year happened in 2004, just as I was perched atop that bustling, industrious colony of ants.

“I wonder if the bats are missing the moths,” my dad says. “What happens when the predators have gotten used to all those bugs? I left the house for a few days and forgot to fill the bird feeder and it took them a few days to come back. Poor birds, probably starving out there.” 


In philosophy, the theory of emergence describes what happens when an entity gains characteristics that its individual parts do not have on their own—characteristics developed when the parts interact to form a whole. I try to imagine humanity a hundred million years from now, evolving toward our own emergence. Where are we, and what kind of accommodations have we made for our new and teeming life? Perhaps we are there in the grass, digging our home, doing our waggle dance, migrating together in search of the next sweet bloom.

Paulina Jenney divides her time between the East Cascades and the Apachian valleys and low hills of southeastern Arizona. Her essays have appeared in Camas Magazine, Terrain.org, Conservation.org, and on Montana Public Radio. Generally interested in seeds, food systems, and the stories we tell at the table, she currently works on federal policy pertaining to plants and intellectual property rights.