Cockroaches play an important ecological role. They are generalist feeders, capable of digesting a wide range of substances due to the variety of bacteria and protozoa in their digestive systems. They help decompose forest litter and animal fecal matter and are, in turn, food for many other animals, including scavengers of dead cockroaches, predators, and egg parasites. They are therefore an important part of the food web. The success of their survival strategies is proven by the longevity of the group and their amazing diversity.
Only about 1 percent of cockroach species are considered pests to humans and these are basically nuisance pests. Cockroaches have earned a bad reputation not only because they feed on human food stores and garbage but because they foul their surroundings, leave behind a repugnant odor, and are extremely difficult to eradicate. However, cockroaches may not be as dirty as they seem. In laboratory experiments, household species are capable of contaminating food and other objects with human disease organisms, but they have not been implicated in actual disease outbreaks. In fact, cockroaches spend a great deal of time cleaning themselves.
Cockroaches have been the target of many insecticides over the years but they have developed resistance to several of them. Attempts to use pheromones as sex lures or to sterilize male cockroaches have thus far not proved practical on a large scale. Sprinkling abrasives such as diatomaceous earth to penetrate their protective cuticles may work in individual households as a nonpoisonous alternative. Once the cuticle is abraded, the roaches die of dehydration. Also effective is boric acid powder, which is both abrasive and poisonous to cockroaches. The best way to prevent cockroaches from multiplying is to keep a clean house and block their access to water, which they need to survive.
American cockroaches are very easy to keep and rear in the laboratory and make excellent subjects for experimentation because of their large size and generalized morphology. They have been the subject of countless studies that have tremendously increased our understanding of insect biology. At least two inoffensive species of cockroaches are kept as pets. These are the large, winged Brazilian cockroach and the Madagascar hissing cockroach.
Scientific classification: Cockroaches make up the order Blattodea, which contains five families. The American cockroach is Periplaneta americana, and the Oriental cockroach is Blatta orientalis, both in the family Blattidae. The German cockroach, Blatella germanica, the Asian cockroach, Blatella asahinai, and the brownbanded cockroach, Supella longipalpa, are in the family Blatellidae. The Madeira cockroach is Leucophaea maderae, the Brazilian cockroach is Blaberus giganteus, and the Madagascar hissing cockroach is Gromphadorina portentosa, all in the family Blaberidae. The remaining families are the Cryptocercidae and the Polyphagidae.