Cockroaches: Blattodea

If they are not controlled, some species may build up huge populations not only in homes and businesses but also in sewers. They are known to carry funguses; bacteria; parasitic worms, worms that infest the cockroaches' internal organs; and other microscopic organisms on and in their bodies that cause diseases in humans. They have the potential for spreading harmful organisms indirectly, through contact with foods and utensils used in home and commercial food preparation areas. There is still no solid evidence that cockroaches spread diseases to humans, but they can trigger allergic reactions among people who are especially sensitive to them. Researchers regularly working with cockroaches in laboratories may eventually become sensitive to them. In time they may experience allergy attacks, asthma, or skin irritations when exposed to cockroaches or the materials with which cockroaches have come into contact.

Pest species are often used for experiments and research in university and government laboratories, studying how their bodies work. Researchers are developing tiny "robotic" cockroaches using the Madagascan hissing cockroach as a model. Equipped with wristwatch-sized sensors and a video camera to help start and steer, the "Biobot" cockroach is able to "see" and take measurements in faraway places that are not safe for humans, such as buildings that have been destroyed by bombs or earthquakes.

Most cockroaches do not live with humans and are not considered pests. Instead, these species live in tropical rainforests, mountains, and deserts. They break down plant materials, recycling them into food that can be used by other plants and animals. In parts of Asia, humans eat cockroaches as food. In southern China and in other parts of the world, dried specimens of Opisthoplatia orientalis are sold for medicinal purposes. And many large cockroaches, such as the Madagascan hissing cockroach, are bred and kept in captivity as pets.