Rock Mountain Shrimp
| Rock Mountain Shrimp | ||||||||||||
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Rock Mountain Shrimp ( Melanoplus spretus ) |
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| Melanoplus spretus | ||||||||||||
| Walsh , 1866 |
The Rocky Mountain Insect ( Melanoplus spretus ), or Rocky Mountain Grasshopper, was the largest grasshopper to be found in the American Midwest and parts of Canada in the late 19th century . It is now considered extinct. The last sighting of a living specimen took place in 1902.
Occurrence and accumulation
The Rocky Mountain Shrimp preferred to haunt prairie areas , but could be found on both sides of the Rocky Mountains . The terrors found good breeding conditions in sandy areas, where they thrived very well in hot and dry climates. In times of drought , the prairie vegetation concentrates its sugar in the stalk, which provided an excellent source of food for the horrors. The heat caused the animals to grow rapidly and they probably moved on the jet stream that swept through central North America.
The swarms were larger than any other locust had seen. A famous 1875 report by AL Child, published by Charles Riley in the Second annual report of the United States Entomological Commission in 1880 , estimated a flock that passed over Plattsmouth , Nebraska , 3,000 kilometers in five days (1880 Miles) at a width of 175 kilometers (110 miles). At around 520,000 km², that would be more than the area of California . The swarm consisted of an estimated 12.5 trillion individuals, with a mass of 27.5 million tons.
Preserved remains of the animals were found in glaciers in Montana and Wyoming , as a result of the swarms crossing the Rocky Mountains. The animals from Knife Point Glacier in northwest Wyoming have been dated to the early 17th century using the radiocarbon method .
Disappear
To date, it has not been satisfactorily clarified why the rocky mountain shrimp died out. Some theories assume that the plowing and watering of the fields by settlers severely disrupted the natural life cycle of the locusts. The last large swarms emerged in the 1870s. The species became extinct about 30 years later; the last living animal was found in southern Canada in 1902. Had the locust not become extinct, it would likely have severely impacted North American agriculture .
Since the migratory phase of grasshoppers only develops under high population densities, there has been speculation that the Rocky Mountain horror could possibly be bred under such conditions from the solitary phase of still existing related short-antennae terrors , but attempts were unsuccessful. As DNA investigations based on museum specimens suggest, the rock hedge was probably a species that was clearly separated from the other species and has therefore definitely become extinct.
Even today, other species of short-antennae terrors cause significant damage to the crop yield in North America, but not to the extent that the rocky mountain shrimp would do.
literature
- John C. Wise: The grasshopper, or Rocky Mountain locust, and its ravages in Minnesota: A special report to the Hon. CK Davis, Governor of Minnesota , 1876
- Jeffrey A. Lockwood: Voices from the Past: What We Can Learn from the Rocky Mountain Locust , American Entomologist, Winter 2001, pp. 208–215 PDF (260 kB)
- Jeffrey A. Lockwood: Locust: The Devastating Rise and Mysterious Disappearance of the Insect that Shaped the American Frontier , 2004, 320 pages, ISBN 0-7382-0894-9
Web links
- Extinction and the American experience - appearance and extinction of the rock insect
- Animal Diversity Web - Classification of the Rock Mountain Insect