Cockroaches are among the most common insects. Based on fossil evidence, cockroaches are known to have been present on earth for over 300 million years. They are one of the most adaptable and successful of the insect groups. There are about 35000 species worldwide and about 60 species that can be found in the United States. We will discuss the most common found here, that is the German cockroach and the American cockroach.


German cockroaches

image of a german roach The German cockroach is the most common of the species found in houses, apartments, restaurants, hotels and other institutions throughout the United States. Adults are pale to medium brown and about ½ to 5/8 inch long, and can be distinguished by the two dark stripes on the pronotum (back). Their nymphs resemble the adults except that they are smaller, wingless, and darker in color, often being nearly black. A single light stripe running down the middle of the back is the most prominent marking on the young cockroach. The German cockroach is a general feeder, but is particularly attracted to fermented foods and beverage residues. If water is present, adults can live about a month without food, but the young nymphs will die of starvation within 10 days. If starved, they become stressed and will forage aggressively for food, even during abnormal periods such as the daytime. These roaches are relatively active, moving around readily within structures. They travel from one location to another and can pass through very small openings. They are also regularly carried from place to place in such things as bagged potatoes and onions, beverage cartons, grocery bags, food carts, and other food packages, handbags, and in the folds of clothing.


American cockroach

image of the american roach Also referred to as the Palmetto bug, it is the largest of the common species, growing to 1.5 inches or more in length. It is reddish-brown, with a pale brown or yellow border on the upper surface of the pronotum (back). Both the male and the female are fully winged. The wings of the male extend slightly beyond the tip of the abdomen, while those of the female are about the same length as the abdomen. The female drops her egg capsule in suitable areas, such as near a food source, or in a protected area. Egg capsules are formed at a rate of about one per a week until from 15 to 90 capsules, each containing 14-16 eggs, have been produced. At room temperature, nymphs will hatch out in 50-55 days. Young nymphs are grayish-brown and each will molt 9-13 times before reaching maturity. After the first few molts, the nymphs become more reddish-brown in color. Indoors, the nymphs and adults are usually found in dark, moist areas of basements and crawl spaces as well as in and around bathtubs, clothes hampers, floor drains, pipe changes and sewers. In basements, they are found in corner areas high on the walls. Outdoors, these roaches are abundant in alleyways, yards, hollow trees and palm tree. The American roach feed on a variety of foods, but decaying organic matter seems to be preferred. They also feed upon bookbinding, manuscripts, clothing and glossy paper with starch sizing. Syrup and sweets are also attractive. The adults have well-developed wings, but seldom fly. They are capable of gliding long distances and will cover considerable distances if they take off from a tree or rooftop.


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