THE INFLUENCE OF CIVILIZATION ON THE 

 INSECT FAUNA IN CULTIVATED AREAS OF 

 NORTH AMERICA^ 



By RoGEK C. Smith 

 Kansas Agricultural Experiment Station, Manhattan, Kans. 



The most striking characteristic of present day civilization is 

 change. Nothing remains stationary or unchanged in the march 

 called progress. Man has taken literally the task of transforming 

 the face of the earth. As a result of his efforts, plant and animal 

 life have been as strikingly affected as the fields and plains. He 

 has, in a large measure, disdained nature's crops and planted crops 

 of his own choosing. Since animals as a group largely depend on 

 plants for food, as the flora changed the fauna followed suit. Man 

 has upset the ancient balance in the cultivated areas, and agricul- 

 ture and biological conditions have been kept in such a turmoil of 

 change that no new balance has been yet set up.^ 



By cultivated areas is meant the farms and gardens, the trans- 

 formed hillsides, valleys, and plains. The transformation has been 

 a replacement of a sod containing many species of plants to a more 

 or less pure culture of one plant. There is also a marked tendency 

 towards specialization of crops involving large acreages in the culti- 

 vated areas of North America. Our attention turns quickly to defi- 

 nite, more or less circumscribed regions, when the following crops 

 are mentioned : Wheat, corn, cotton, citrus, sugar cane, sugar beets, 

 apples, peaches, plums, blueberries, dates, and celery. This speciali- 

 zation tends to upset the balance even more completely than if the 

 crops were generally diversified. 



Plowing up the native sod, clearing the forests, and watering the 

 desert affected markedly the insect fauna of the region. The cli- 

 mate, meteorologists claim, has not been appreciably affected by 

 these activities, but soil climate has been markedly affected. So the 

 greatest factor has been the change in food plants for the hosts of 

 insects. 



1 Contribution no. 404 from the Department of Entomology. Reprinted by permission 

 from Annals of the Entomological Society of America, vol. 26, no. 3, September 1933. 



^ Smith, Roger C. Upsetting the balance of nature, with especial reference to Kansas 

 and the great plains. Science, vol. 75, pp. 649-654, 1932. 



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