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Cockroaches
Nature Bulletin No. 483-A   march 3, 1973
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation

COCKROACHES
The cockroach, one of our most obnoxious pests, is the most ancient of living insects. During the Coal Age -- that warm humid swampy period some 250 million years ago -- cockroaches ruled the insect world and they differed only in minor ways from the modern ones. Today there are about 1200 species, almost all of tropical origin. Some are less than one-half inch in length and others are as much as 6 inches long; some are vegetarians but many are omnivorous. Although abhorred and hated, a few kinds have spread all over the world and have been able to live with man in spite of his efforts to exterminate them.

A domestic cockroach has a flat shiny body that enables him (or her) to slip through narrow cracks and hide in dark warm places; he usually comes out in search of food at night; he can run swiftly; he is a scavenger that will eat almost anything; he is very prolific; he is sly and adaptable. Although he cannot stand extreme cold, he has almost no natural enemies. It is interesting to watch one of these wary insects. Its long whip-like antennae, longer than the body, are constantly waving to and fro in search of food and to warn of danger. It frequently grooms itself by drawing each leg, and then the antennae, through its mouth.

Cockroaches are abominated because of what they contaminate with their feet and their excretions, rather than for what they consume. Traveling, across decaying matter and filth, they may spread the germs of diseases such as dysentery, typhoid, tuberculosis and cholera, Since they thrive and are difficult to control in homes, restaurants, hospitals, bakeries, meat markets and food factories in spite of sanitary measures, they are a menace to public health. Where numerous, they are said to have an offensive odor. About the only thing in their favor is that they prey on bedbugs.

The cockroach has six long spiny legs; a small head, with chewing mouthparts, bent downward and backward; and its four wings, if it has any, lie flat on its back but are seldom used. Depending upon the species and sex, the wings may be well-developed, or short and weak, or absent. The eggs are enclosed in a leathery capsule or "pod" which the female hides away unless, as in the case of the German Cockroach, she carries it around (protruding from her abdomen) until they are ready to hatch, The young resemble their parents and pass through several molts as they grow to become adult.

There are about 55 species of roaches in the U. S. but, except in certain localities, only 5 or 6 are serious pests. These were introduced from foreign countries. The worst is the tan-colored German Cockroach about one-half inch long. It has more eggs per capsule (24 to 48), matures more quickly, and produces far more offspring per year than any other species. The Oriental Cockroach, much larger and almost black, is the most disliked because it commonly lives on filth. The American Cockroach is the largest, about 1-1/2 inches long, and reddish brown. The young may require more than a year to become adult. Others, less common, are the Brown-banded, Australian, Surinam and Smoky Brown Cockroaches. The Wood Roach, resembling the American but with white edges along its sides, is native here. Often found in hollow trees or under loose bark and wood piles, it sometimes invades houses.

Years ago, cockroaches could be controlled only by cleanliness and the use of a poisonous dust, such as sodium fluoride. Since World War II, liquid chlordane, applied as a spray, has been most effective. If the insects develop a resistance to it, then a more deadly insecticide is used.

For best results, employ a professional pest control operator.


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