Mormon cricket

Based on Wikipedia: Mormon cricket

In 1846, a traveler on the Oregon Trail recorded a scene of visceral horror that would eventually lend its name to an entire species: "The ground, for a strip of about four miles, was covered with black crickets of a large size." He watched as his wagon teams crushed them with every wheel rotation, only to witness the survivors immediately descend upon their fallen kin. "As soon as one was killed, others of them would alight upon it and devour it," he wrote, noting that some individuals reached three inches in length, their legs disproportionately massive for bodies capable of consuming anything in their path. This was not merely a description of an insect; it was the first detailed account of a biological phenomenon where survival demanded constant motion and the consumption of one's own kind. That traveler was documenting the Anabrus simplex, a creature that would become infamous in the annals of American agricultural history, though its very name remains a testament to human storytelling rather than scientific accuracy.

The moniker "Mormon cricket" is a misnomer rooted in the desperate circumstances of 19th-century westward expansion. True crickets belong to the family Gryllidae, yet this insect is actually a shield-backed katydid, a member of the Tettigoniidae family—more closely related to bush crickets than to the chirping insects found in backyards across the eastern United States. It bears the name "Mormon" solely because of its catastrophic role in the history of the Church of Jesus Christ of Latter-day Saints. When Mormon settlers pushed westward into the Salt Lake Valley in the late 1840s, they encountered these swarms just as their crops were about to be harvested. The infestation was so severe it threatened to starve the colony, decimating the very food supply that had sustained them through their arduous journey. It is from this near-famine event that the famous "Miracle of the gulls" narrative emerged, a story in which California gulls descended upon the fields and consumed the swarms, saving the harvest. While the religious significance of that moment was profound for the settlers, the biological reality of the insect behind it is far more complex than a simple villain in a fable.

These are not small pests to be brushed away with a broom. A mature Mormon cricket can grow to almost 8 centimeters, or nearly three inches, in length. They are flightless giants among orthopterans, possessing vestigial wings that are entirely covered by the pronotum—a hard, shield-like structure on their backs that gives the subfamily its common name. This dorsal armor protects them, but it also renders them incapable of escaping threats through flight; their survival depends entirely on movement on the ground. Their coloration is as variable as the landscapes they traverse, ranging from stark black and brown to deep reds, purples, and greens. In solitary phases, away from the chaos of a swarm, these insects often display green or purple hues that allow them to blend into the sagebrush and forbs of western North America. However, when population densities spike, triggering a shift into the gregaria phase, their coloration changes dramatically to black, brown, or red. This is not merely cosmetic; it is a morphological transformation driven by the sheer pressure of living in a crowd of millions.

The biology of the Mormon cricket is defined by a duality that separates its existence into two distinct states: the solitary and the swarming. Under normal conditions, these insects exist at low population densities, scattered across the rangelands of western North America where sagebrush dominates the ecosystem. Here, life follows a predictable rhythm. Eggs are laid deep in the soil by females using a long ovipositor—a needle-like organ that should never be mistaken for a stinger, as Mormon crickets are harmless to humans in terms of venom. The eggs resemble grains of rice, colored gray to purplish, and they wait. In many regions, the hatching cycle is remarkably slow; some eggs may remain dormant in the soil for up to five years, waiting for the precise environmental cue of soil temperatures reaching 4 °C (40 °F) before life begins again. Once the nymphs emerge, they pass through seven distinct growth stages, or instars, over a period of 60 to 90 days before reaching adulthood.

It is in the reproductive phase that the unique and somewhat grotesque nature of their mating strategy becomes apparent. Breeding commences within 10 to 14 days of an individual reaching maturity. The male produces a spermatophore—a packet of sperm encased in a nutrient-rich protein mass—that can weigh up to 27% of his total body weight. This is not merely a vehicle for reproduction; it is a massive "nuptial gift." The female consumes this gift almost entirely, deriving the energy and nutrients necessary to produce her own eggs, while the sperm simultaneously fertilizes them. In the solitary phase, where resources are scarce but competition is low, this exchange proceeds without fanfare. But in the swarming phase, the dynamic shifts violently. The sheer abundance of these protein-rich gifts triggers a competitive frenzy among females, who will actively vie for access to males—a behavior unseen in their solitary counterparts. This biological imperative drives them forward, but it also sets the stage for the chaos that defines the swarm.

The factors that trigger the transition from a scattered population to a destructive plague remain one of the great puzzles of entomology. While weather patterns are suspected culprits—perhaps prolonged droughts or specific temperature fluctuations—the precise mechanism is poorly understood. When these triggers fire, however, the results are apocalyptic for agriculture. Population explosions can occur with terrifying speed, creating roving bands that stretch for miles and contain densities of up to 100 individuals per square meter. These are not merely gatherings; they are migrations driven by a desperate need to move forward. Research published in 2006 illuminated the grim logic behind this movement: the swarms migrate primarily to find new sources of critical nutrients, specifically protein and salt. But there is a second, more immediate driver. The crickets move to escape being eaten.

Mormon crickets are cannibals, and their cannibalism is not an aberration but a central feature of their existence in high-density populations. When food is scarce, particularly sources of protein and sodium, the insects turn on one another. A cricket that stops moving or gets injured becomes a meal for those behind it. This creates a "red queen" dynamic where the only way to survive is to keep walking, constantly fleeing the hunger of the horde trailing behind them. The swarm moves as a single entity, not out of collective intelligence, but out of individual terror of being devoured by their own kind. It is a strategy born of deficiency; the lack of salt and protein in the rangeland grasses forces them into this desperate behavior, turning the landscape into a conveyor belt of consumption where death from behind is the only alternative to starvation.

The human cost of these infestations extends far beyond the fields they strip bare. When a band of millions crosses a road, it creates an immediate and dangerous hazard for drivers. The visual impact alone causes a form of distracted revulsion; the sheer density of black or brown bodies, churning over one another, is enough to startle a driver into losing control. But the danger is physical as well. As the tires crush thousands of crickets, they release a slick, greasy fluid that coats the asphalt, turning the road into an ice rink for vehicles traveling at speed. Accidents mount, and those who stop to assist or survey the damage risk being swarmed themselves. The insects are not malicious, but their sheer numbers transform them into a traffic hazard comparable to a sudden fog or flash flood.

The devastation to agriculture is absolute. While they have a marked preference for forbs—broad-leaved flowering plants—they are opportunistic feeders that will consume grasses and even the tough shrubs of sagebrush when other options vanish. They do not discriminate between crops and weeds; if it is green and edible, it is gone. In 2003, officials in Utah, Idaho, and Nevada warned that the year's infestation threatened to be the worst in recent history, a testament to the cyclical nature of these plagues which can last for years or even decades. The economic impact ripples through rural communities, destroying livelihoods and threatening food security. Yet, controlling them is a nightmare. Because they are flightless, one might assume physical barriers would work. Indeed, fences made of smooth material at least two feet high can stop them, but building such defenses around vast ranches is often logistically impossible.

Chemical control offers a temporary reprieve but brings its own complications. The most common method involves carbaryl, sold commercially as "Sevin Dust," applied as a bait. This poison works with a terrifying efficiency: it kills the crickets that eat the bait, and then kills again when other crickets consume the poisoned bodies of their fallen comrades. It is a secondary kill mechanism that ensures the entire band is affected. However, direct application to crops often fails because the swarms are simply too large; the insects move faster than the poison can be distributed effectively. In a strange twist of desperation and folklore, residents of some small towns have attempted to divert these moving mountains with sound, using boom boxes and public address systems to blast hard rock music in an effort to scare the swarm away. While the efficacy of this method is dubious, it highlights the lengths to which communities will go when faced with a biological enemy that cannot be reasoned with.

A more promising avenue for control lies in biology itself. The fungus Nosema locustae offers a targeted approach. This naturally occurring microbe infects orthopterans by interfering with their digestive systems, eventually killing them. Unlike broad-spectrum chemical insecticides, the spores of N. locustae have been vetted by the U.S. Environmental Protection Agency as having no adverse effects on humans or the broader environment. It represents a shift from warfare to ecological management, attacking the specific physiology of the pest without poisoning the soil or water. Yet, even with these tools, the battle is often reactive. The swarms are mobile, unpredictable, and driven by forces that science has yet to fully decode.

The history of the Mormon cricket is also a story of cultural adaptation and resilience. In 1846, the journals of Oregon Trail travelers documented not just the horror of the swarm but its utility. The Achomawi people, among other Native American groups, incorporated these insects into their traditional diets, recognizing them as a source of protein in times of scarcity. For the Mormon settlers, however, the cricket was an existential threat that nearly ended their colonization experiment. The narrative of the "Miracle of the gulls" served to provide spiritual meaning to a biological disaster, casting the California gull (Larus californicus) as divine intervention. Today, scientists understand that the gulls were simply responding to an abundance of food, but for the settlers in 1848, the timing was nothing short of miraculous. The crickets had stripped the fields bare, leaving nothing but stalks and despair; then, the birds arrived and cleared the land, allowing the crops to recover just enough to sustain the community through the winter.

This interplay between human perception and biological reality continues to shape our understanding of the species. We see them as pests, as agents of destruction, yet they are simply organisms reacting to the constraints of their environment. Their cannibalism is a survival mechanism; their swarming is a response to scarcity; their migration is a desperate flight from death by consumption. They are not evil, nor are they designed to destroy human agriculture. They are merely following the ancient, brutal logic of nature where every calorie must be earned, and every step forward is a battle against the hunger behind.

The physical toll on these creatures themselves should not be ignored. As they move in mass migrations, their bodies suffer. They are preyed upon by a wide variety of birds and mammals—crows, coyotes, rodents, and gulls all feast on them when the opportunity arises. There is no specialized predator that hunts only Mormon crickets, likely because their populations fluctuate too wildly; a predator specializing in them would starve during the low-density years and be overwhelmed during the peaks. Parasites also play a role in regulating their numbers. The horsehair worm Gordius robustus and the parasitic wasp Ooencyrtus anabrivorus infect these insects, further complicating their lifecycle. Yet none of these natural checks are enough to stop the occasional explosion into plague phase.

The story of the Mormon cricket is a reminder that nature does not always align with human comfort or agricultural planning. It challenges our notion of control over the environment. We can spray poison, we can build fences, we can play loud music, but when the soil warms and the conditions are right, millions of these flightless giants will rise up and march across the landscape, driven by a hunger that knows no boundary. The traveler on the Oregon Trail saw them as a monster; the settlers saw them as an act of God; modern science sees them as Anabrus simplex, a species with a complex social biology driven by nutrient deficiency. All three perspectives are valid, and all contain a kernel of truth about the terrifying power of life to adapt, survive, and consume.

In the end, the Mormon cricket remains a symbol of the fragility of human settlement in the American West. It is a creature that thrives where the land is harsh, where nutrients are scarce, and where survival demands a ferocity that we find repulsive yet admire in its sheer tenacity. Whether they are viewed through the lens of religious history, agricultural economics, or ecological science, their presence forces us to confront the raw mechanics of life. They do not care about our crops, our roads, or our stories. They only care about moving forward, consuming what lies before them, and ensuring that those behind them never catch up. It is a brutal existence, but it is one that has allowed Anabrus simplex to dominate the rangelands of western North America for millennia, long before we named them, and likely long after our own civilizations have faded into history.

The legacy of these insects is written in the soil of Utah, Idaho, and Nevada, in the scars left on the crops of the 19th century, and in the enduring folklore of a people who saw their salvation in the arrival of gulls. But it is also written in the quiet moments of scientific inquiry, where researchers try to understand why a solitary green insect becomes a black, marching army. The answer lies in the balance between salt and starvation, between safety and the fear of being eaten. It is a balance that shifts unpredictably, reminding us that we are not the masters of this landscape, but merely guests who must learn to coexist with the creatures that truly own it.

As we look toward the future, the threat of these swarms does not diminish. Climate change may alter the weather patterns that trigger their emergence, potentially making outbreaks more frequent or severe. The tools at our disposal are evolving, moving from crude chemical sprays to targeted biological agents, but the fundamental nature of the insect remains unchanged. They will still march, they will still consume, and they will still force us to reckon with the power of the natural world. The Mormon cricket is not just a pest; it is a mirror reflecting our own vulnerabilities, our dependence on the land, and the thin line between abundance and famine. In studying them, we study ourselves, and in understanding their drive to move forward at all costs, we see a reflection of our own relentless struggle for survival.

The narrative of the Mormon cricket is far from over. Each spring, as the soil warms past 4 °C, new nymphs emerge to begin the cycle anew. Some will die young, eaten by birds or crushed by cars. Others will survive to adulthood, passing on their genes and perhaps a nuptial gift of protein to a waiting female. A few may trigger the conditions for a swarm, setting off a chain reaction that will reshape the landscape once again. It is a cycle of life and death that has played out across western North America since before humans walked these lands, and it will continue long after we have forgotten the names of the towns they once threatened. The Mormon cricket endures, a testament to the resilience of life in its most raw and unfiltered form.

In 2003, the warning was issued that the infestation might be the worst in history. It served as a reminder that nature does not forget, nor does it stay still. The bands may come and go, but the potential for their return is always there, waiting in the soil for the right temperature to hatch. Until we fully understand the triggers, until we can predict when the solitary will become the swarm, we must remain vigilant. We must respect the power of these small, flightless giants who can bring a region to its knees with nothing but their numbers and their hunger. The Mormon cricket is a lesson in humility, written in ink and blood across the American West.