American Cockroach

The American cockroach (Periplaneta americana) is the largest pest cockroach found in Australian homes, growing to 35–40 mm in length with a shiny reddish-brown body, a pale yellow border around the upper thorax, and a yellowish figure-eight marking on the shield behind the head. Males have wings extending beyond the abdomen, and in warm conditions the species can fly short distances — a trait that separates it from the smaller, flightless German cockroach. It favours warm, moist, dark locations and is most common in coastal areas, living around sewers, grease traps, rubbish dumps, and in roof, wall and subfloor voids rather than open living areas, and is also frequently found around hospitals, bakeries, food stores and factories. Indoors, inspect floor drains, laundries, bathrooms, basements and gaps around pipework, particularly at night when this fast-moving, nocturnal insect is active — a torch inspection after dark is often more productive than a daytime search. Look for tiny dark droppings and faecal smears, shed nymph skins, and purse-shaped egg cases, each holding 12 to 16 eggs, glued near food and water sources; a single female can produce up to 50 of these cases in her lifetime. A musty odour in enclosed roof voids or wall cavities can also signal an established population. Victoria Department of Health details this species' habitat, reproduction and detection signs, and the Australian Environmental Pest Managers Association confirms its distinctive figure-eight marking.