The name “cockroach” comes from the Spanish word for cockroach, cucaracha, transformed by English folk etymology into “cock” and “roach”. An adult female cockroach produces an egg capsule, called an ootheca. The ootheca will be carried during incubation period and then drops until eggs are ready to hatch. Immediately after molting, cockroaches are white, but their outer covering darkens as it hardens, usually within hours. Cockroaches are nocturnal. They hide in dark, warm areas, especially narrow spaces where surfaces touch them on both sides. Immature cockroaches tend to stay in even smaller cracks where they are well protected. Cockroaches tend to congregate in corners and generally travel along the edges of walls or other surfaces. They leave chemical trails in their feces, as well as emitting airborne pheromones for swarming and mating. They have broad, flattened bodies and relatively small heads. They are generalized insects, with few special adaptations, and may be among the most primitive living neopteran insects. Cockroaches threaten human health because they transmit or aggravate many serious diseases, including food poisoning, asthma, Hepatitis E and diarrhea.
Here are the commonly found species in Malaysia:
The American cockroach, Periplaneta americana, prefers warm and humid environments, usually with temperatures in excess of 82°F. They are also common in sewers, steam tunnels, and masonry storm drains. Occasionally they forage from sewers and other areas into the ground floor of buildings. The egg cases, which are about 3/8 inch long, are brown when laid but turn black in 1 to 2 days. Each egg capsule contains about 12 young; a female and her offspring can produce over 800 cockroaches in one year.
The German cockroach, Blattella germanica, is the most common indoor species, especially in multiple-family dwellings. They prefer food preparation areas, kitchens, and bathrooms because they favor warm (70° to 75°F), humid areas that are close to food and water. This species reproduces the fastest of the common pest cockroaches: a single female and her offspring can produce over 30,000 individuals in a year. Each egg case contains about 30 young, and a female may produce a new egg case every few weeks.
The oriental cockroach, Blatta orientalis, is sometimes referred to as a water bug or black beetle. It lives in dark, damp places like indoor and outdoor drains, water control boxes, woodpiles, basements, garages, trash cans, and damp areas under houses. At night, oriental cockroaches may migrate into buildings in search of food. They usually remain on the ground floor of buildings and move more slowly than the other species. Each female and her offspring can produce nearly 200 cockroaches in one year. Development from a newly emerged nymph to adult can take from 1 to 2 years or more.
The brownbanded cockroach, Supella longipalpa, is not as common as the German cockroach. This species seeks out areas that are very warm most of the time. Favorite locations include near the warm electrical components of appliances such as radios, televisions, and refrigerators. Brownbanded cockroaches prefer starchy food (e.g., glue on stamps and envelopes), are often found in offices and other places where paper is stored, and are more common in areas that are not air conditioned. Adult males sometimes fly when disturbed, but females do not fly. Each female and her offspring are capable of producing over 600 cockroaches in one year.