Locust: The Devastating Rise and Mysterious Disappearance of the Insect That Shaped the American Frontier by Jeffrey A. Lockwood

Author:Jeffrey A. Lockwood
Language: eng
Format: mobi, epub
Tags: West, Insects & Spiders, West (U.S.), HI, CO, Nature, Entomology, Rocky Mountain locust, World, 19th Century, State & Local, Animals, Non-fiction, Science, CA, United States, Rocky Mountain locust - West (U.S.) - History, ID, History, West (AK, Life Sciences, UT, Library, MT, NV, Zoology, WY)
ISBN: 9780465041671
Publisher: Basic Books
Published: 2005-02-15T00:35:28.022941+00:00

A NEW KIND OF METAMORPHOSIS

In his twenty-nine-page paper, Uvarov undertook what is called a taxonomic revision. In biology, the naming of species and their proper assignment to a particular genus are matters of continual investigation. Often we discover specimens or anatomical features that make us rethink whether a species has been properly described, named, and grouped. The goal is to have our taxonomy reflect the underlying biology that defines a species—the sharing of genetic material. Because we rarely have the time or opportunity (the seeming impropriety of biological voyeurism being of less concern) to follow creatures around and see if they are mating and then track the females to see if their offspring are viable, taxonomists use the bodies of organisms as surrogates for genetic similarity. Creatures that look the same presumably have a common gene pool. This approach has recently been challenged by our ability to more directly assess genetic similarity with molecular techniques. Zoologists are finding that sometimes animals that are physically indistinguishable do not share a genetic heritage. However, in 1921 Uvarov was struggling with the opposite problem. He was convinced that what earlier taxonomists had described as two species were really one.

Uvarov introduced his study by noting, “The literature on the economics, biology and especially on the means of control of these locusts is enormously extensive, but at the same time their systematic arrangement is in considerable confusion, and extremely contradictory opinions as to the mutual relationship of the different so-called species exist among specialists.” His particular concern was related to two species that to most people were so clearly different that no confusion should have been possible: Locusta danica and Locusta migratoria . The former species was a grasshopper leading a rather solitary existence and creating no fuss on the part of farmers. But the latter species congregated in staggering numbers, maturing into the devastating swarms of migratory locusts that had caused famines for centuries in Central Asia. The ecologies of the two species were completely divergent. Danica was found in many habitat types, including dry grasslands, but migratoria was largely restricted to the basins of the Caspian and Aral Seas and Lake Balkash. The locust bred in the reeds of the river deltas, from where the immense swarms would emanate and sweep across the fertile irrigated farmlands of the region.

Based on anatomical appearances, the two species seemed to have very little in common. Danica was a bright green creature, whereas migratoria was quite variable but often black and orange red. The females of danica were much larger than the males, while in migratoria the sexes were nearly the same size. Uvarov also noted that the body of migratoria was very well suited for flight, with impressively elongated wings and a body filled with air sacs, which he noted were “described long ago by American entomologists in the Rocky Mountain locust, and occurring doubtless in all other migrating species of locusts.”

So, if the two species lived in different habitats, behaved in dissimilar ways, and looked

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