They darkened the skies. People couldn’t even begin to imagine how many there were. And if you went back in time and said they would be extinct in 50 years, they would have locked you up.


No, not Ectopistes migratorius; Melanoplus spretus.


Jeffrey Lockwood teaches natural science and humanities at the University of Wyoming; his particular science specialty is entomology, and within that, grasshoppers. He’s written a slightly uneven but generally good account of the Rocky Mountain Locust, a creature you’ll be familiar with if you’ve ever read Giants in the Earth or On the Banks of Plum Creek. The most famous swarm, nicknamed “Albert’s Swarm” after Signal Corps meteorologist Albert Cline, contained around 3.5 trillion locusts. Given that it was 1875, one might suspect panicked exaggeration, but Dr. Cline was a pretty meticulous observer. He telegraphed other weather stations to find out if they were also experiencing a plague of locusts to get the length; timed locust velocity (around 15mph) and passage time to get the width; and estimated the depth of the swarm by turning a telescope upward and focusing until he could see individual locusts, then turning it horizontally and finding a terrestrial object of known distance that was also in focus. The swarm was 1800 miles long, 110 miles wide, and one quarter to one half mile deep. So around 200K cubic miles of locusts. Dr. Cline commented “This is utterly incredible, but how can we put it aside?”


People on the ground were understandably more than a little freaked out. The locusts ate crops. And weeds. And trees. And wool, leather and cotton when they ran out of greenery. (No one mentions anthropophagy, but there are some reports of bites, and I certainly wouldn’t want to be trapped motionless under something like that). Predators had a field day, of course, but chicken meat was supposedly rendered foul-tasting by locust consumption, and turkeys ate until they died.


And then, seemingly, that was that. There were smaller but still devastating swarms afterward, but they tapered off, and the last known swarm of Melanoplus spretus was reported from Canada in 1902. Individuals were reportedly collected as late as the 1930s, but locust taxonomy depends on configuration of the genitalia and surviving pinned specimens often aren’t sufficiently intact to verify species.


Lockwood gets a little digressive here, recounting the history of American economic entomology. There are some interesting characters here, as with all 19th century science, but this section drags a little. Things pick up somewhat with a discussion of locust taxonomy and ecology (surprisingly, perhaps, as taxonomy is usually pretty dull for nonenthusiasts). Work in Russia and South Africa had demonstrated that locusts there had a complicated life history. The ordinary forms looked like more or less typical grasshoppers, but careful research found that crowding and exposure to locust feces could induce generation of a swarming phase that looked so different it had previously be considered a distinct species (living locusts didn’t change, but the next batch out of the eggs did). Naturally, it was assumed the North American form was similar, and entomologists in the 1930s to 1950s spent quite a bit of time trying various combinations of crowding, temperature, humidity and whatnot on caged populations of Western grasshoppers trying to get them to change into locusts. Didn’t happen; apparently the Rocky Mountain locust didn’t go through phases.


Lockwood then recounts his own research efforts, trying to find frozen Melanoplus spretus in various glaciers in the American west to see if he could get usable DNA and recognizable genitalia. He was eventually successful, discovering to some surprise that the closest related species based on molecular data was rather distant based on physical characters. Lockwood expresses a little sour grapes here; he had quite a bit of trouble getting his research funded and published; one journal editor sent his submission back snarking he was “confusing natural history with science” because his work was descriptive rather than experimental. (His funding all came from private sources; although he doesn’t comment on it I can imagine what would happen if a US Congressperson discovered the NSF was sending people on hiking trips in the Rockies to study frozen grasshopper penises). Eventually, though, he presented enough data that the current paradigm in Rocky Mountain locust research is that Melanoplus spretus was a unique locust species that was responsible for the 19th century swarms; that it is not a swarming phase of an otherwise familiar grasshopper; and that it is now extinct.


The explanation for the sudden decline and extinction is plausible but not proven. Lockwood speculates that the locust may have had refugia habitat in the Rockies – somewhat similar to Monarch butterflies, where 95% of the population migrates to a few groves of trees in the mountains around Mexico City. A couple of unscrupulous loggers could destroy almost all the butterfly population in a few days. The theory is that Melanoplus spretus depended on specific soil types in a few Rocky Mountain valleys to sustain a population between swarms, and once those areas were destroyed by mining or grazing or agriculture that was it. To his credit, Lockhart is not a sentimental environmentalist of the “only Man is vile” school; he points out that there is no “balance of nature” that “Man” is somehow responsible for maintaining and that locusts have to play the cards they draw in the natural selection sweepstakes just like everything else. (In fact, he suggests that if a relict population of Melanoplus spretus was discovered somewhere, it might be perfectly justifiable to wipe it out, on the grounds of the potential damage a 21st century swarm could do). There is a little grumbling about global warming, which seemingly doesn’t fit well with the previous statement; yet there is some personal justification here as the “Grasshopper Glaciers” of the Rockies are disappearing fairly rapidly – a couple of tons of soggy locust corpses weather out every season – and they are vital to Lockwood’s research. I was prepared to make a standard argument here – if things are melting out of glaciers now, that implies that at the time they froze into the glacier the glacial extent must have been about the same as it is as present; however Lockwood anticipates that (although not explicitly) by noting that things can migrate through glacial ice from their initial position. Not quite sure if that can be done with well-preserved grasshopper bodies, but I’ll give it the benefit of the doubt.


Lockwood concludes with a tantalizing hint that just maybe the story isn’t over; he examined a few grasshoppers in Yellowstone National Park that didn’t quite fit the morphological profile of anything but Melanoplus spretus. Having no collecting permit, he wasn’t able to dissect them and examine the genitalia; however, they were in exactly the type of high valley that he speculated was the refuge habitat for the Rocky Mountain Locust. And, of course, Yellowstone, established when there were still massive locust swarms, was never grazed or mined or farmed or whatever it was that did in the other supposed habitats.


A bit disappointing in the illustration department; Lockwood uses only 19th century drawings of the species, its habits, and its presumed range. I would have liked to see a little more explanation of how DNA analysis works and some pictures of the characteristic genitalia (especially because the text refers to parts by their technical names). The bibliography is short but useful; however there are no reference notes in the text. As mentioned, the chapters about early North American entomologists drag a little. Still an engaging read. ( )

Professor Lockwood has written a very readable study on the Rocky Mountain Locust, the insect that plagued the plains in the 1870s. Beginning with the historical record, outlining the men who made a lifetime of studying the insect and ending with a discussion of why this plague disappeared, Lockwood describes what we have done to the ecology in our time on this continent. Anyone that believes we leave no imprint on nature should read this book. ( )

In the late 1800's Americans were struggling to settle the west, a barren inhospitable wasteland with very little farmable land. If the farmers didn't have it rough already, it was horrifying when out of nowhere great swarms of locusts descended on their crops and rapidly consumed everything they worked so hard for right before their eyes.

The Rocky Mountain locust was certainly a pest, but the most curious thing about them is their sudden disappearance. Great swarms of these insects caused mass starvation and mayhem and them simply vanished. It's unimaginable that something that created so much terror among such a vast area of the country could go extinct, but it happened.

Lockwood writes with a passion and his involvement with the investigation of the locusts makes the book all the more compelling. He discovered Rocky Mountain locust samples frozen within glaciers in Wyoming and came up with a popular hypothesis as to the disappearance of the insects, which he pitches at the end of the book.

I won't say I'm not skeptical of Lockwood's hypothesis, but I found the book a joy to read and educational to boot. Fascinating and enlightening, as any good nonfiction ought to be. ( )

This is an interesting tale about the apparent extinction of the Rocky Mountain Locust, which so devastated the farms of the early settlers of the American West.

Lockwood begins his tale with a rather exhausting recitation of the first hand accounts of the Locust swarms, and the impact they had on the pioneers. This was, we quickly learn, horrifying and almost unbelievable to modern ears. The helplessness and despair, starvation and economic ruin! Lockwood's account is to this reader, at least, could have been a little shorter--I got to the "enough awready" stage pretty soon. But it does set the stage for the question (which I had wondered about myself): what happened to them? Why haven't they recurred over the last century? Might they come back?

Lockwood, as a young professional entomologist, was unhappy with previous explanations and decided to try to answer this question with as much certainty as he could, using real data and a little less speculation. He relates the historical hypotheses in some detail, showing the reader their inadequacies in a pretty convincing way. A nice approach is that he provides lots of biographical detail of the earlier entomologists who were concerned with the mystery, which livens up the tale too. By the time he got to his own explanation, I was ready for it, and was pretty well convinced to boot.

I especially appreciated the way he consistently tried to get quantitative about various aspects of the problem. He doesn't just say that the swarms were awful big, but calculates that the biomass at times was as large as all the buffalo in the West. There are numbers here. I like that.

I was interested to read about his expeditions to find remnants of the swarms on glaciers, his trials with getting funding and published, and the passion he has for his subject. I was a little amused by the sympathy he develops for the locust, which sometimes even veers toward a mystical reverence for them, and a regret for their passing. Not many pioneers felt that way, I think.

The twist at the very end of the book was quite startling to me. I wonder, will anyone follow up on it?

The book is a little long-winded to some, perhaps, but I appreciated the thoroughness with which he approached the work, and found it to be quite fascinating, and thought his work to be something of a triumph. I was satisfied. ( )

The Rocky Mountain Locust extinction.