Many people know something about Old World locusts, if only through the book of Exodus. But they are unaware of the most astounding entomological phenomenon in North American history. For centuries, swarms of the Rocky Mountain locust, Melanoplus spretus swept across the continent, outweighing the bison population of North America. 19^th century pioneers were subsistence farmers, meaning they grew crops to feed themselves, so they faced starvation when locusts arrived (much like many African agriculturalists who battle desert locusts today).

Finding the ecological origin of the Rocky Mountain locust outbreaks was a challenge for scientists in the 1800s. Through extensive explorations, they discovered the “Permanent Zone” where the insect could always be found, at least in low densities, and from which swarms emerged. This region encompassed the fertile, well-drained river valleys of the Rockies, which provided consistent food for the insects and optimal soil for their eggs. This sanctuary of the Rocky Mountain locust was similar to both contemporary wildlife sanctuaries and habitats that support some of the Asiatic locusts.

People used a wide range of methods to battle the Rocky Mountain locust. For example, the government paid bounties for bushels of locust eggs. Once the locusts hatched, hand-dug ditches made effective pitfall traps. Effective (and dangerous) insecticide formulations were from bran baits laced with lead and calcium arsenate. Various horse-drawn implements were invented to crush the nymphs. The most popular device was the “Hopperdozer”—a large, flat pan coated with coal-tar and dragged through a field, forcing nymphs to hop into the gunk.

In 1875, a mega-swarm of 3.5 trillion locusts—more 100-times greater than the largest known swarm of the desert locust—devastated crops. After small swarms formed again in the 1890s, farmers expected more outbreaks. But in 1904, the last living specimen of the Rocky Mountain locust was collected in Manitoba. The species disappeared—forever.  

What could explain the disappearance of an organism that spread from California to Missouri and from Texas to Canada? Solving this great ecological mystery required understanding both the Rocky Mountain locust’s biology and North America’s history to grasp how European settlement collided with this insect species.Many hypotheses were developed, including: ecological linkages between the locust and alfalfa (one of the few plants that didn’t benefit these insects), climate change (the end of the so-called Little Ice Age came in the 1800s), the decline of the bison (which were thought to provide habitats favorable to the locust), and the diminishment of fire (used by indigenous people to maintain vast swaths of prairie). However, all of these explanations were refuted by evidence. There didn’t seem to be any large-scale ecological change corresponding to the disappearance of an insect that could blanket much of North America. And therein lay the key. 

The mystery was solved by understanding that locusts passed through ecological bottlenecks. During recessions, the species was restricted to their Permanent Zone. And in the late 1800s, the mountain valleys were converted to agriculture to feed the burgeoning gold and silver mining operations. The sanctuaries of the locust were plowed, irrigated, grazed, harrowed, flooded, and trampled just when the insect was most vulnerable. The Rocky Mountain locust succumbed to unwitting habitat destruction.  

Locust outbreaks forced the United States to confront three sociopolitical issues. First, this insect brought into sharp relief the conflicting ideals of agrarianism and industrialism; having fertile land did not assure success. Next, these creatures compelled people to confront the nature of poverty; hard work did not assure survival. Finally, the locusts forced the government to come to terms with its obligations to the people; in times of need public assistance was required. 

The Rocky Mountain locust presents a morally complex story. On the one hand, the devastation by these insects caused terrible suffering, so their extinction was a good thing. On the other hand, wasn’t something of value lost with the loss of this remarkable species? North America will never again experience a biological eclipse of the sun. Our world is safer—and less alive.

This epic tale of mysterious disappearance provided the foundation for Locust: The Opera. This performance intertwines the ecology of the Rocky Mountain locust with our history of both courage and fear through music, lyrics, costuming, scenery, and action. You are invited to take an hour to see what can happen when scientists and artists collaborate:

1.    Scene I https://youtu.be/L_4xzj7gAjA
2.    Scene II https://youtu.be/KyK4jQwcfcw
3.    Scene III https://youtu.be/tuq1U815e6Q

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