Cockroaches, a frequent pest in households, belong to the Blattodea order, which includes insects like termites and mantids. They have a flat body structure, long and slender antennae, and six legs. These omnivorous creatures can consume anything from plants and other insects to human food. They can survive in any environment with a food source, hence their presence on every continent except Antarctica.
Discovering a cockroach infestation in one’s home is undesirable, primarily because they are not only difficult to eradicate but also quite unhygienic.
Recognising different cockroach species is crucial as each species varies in appearance, habitat, life cycle, and diet. Knowing the type of cockroach can aid in more effective pest control treatment.
Here are the six most common cockroaches in Australia, along with their unique characteristics:
Australian Cockroach (Periplaneta australasiae): This reddish-brown cockroach, often mistaken for an American cockroach due to the yellow stripe across its head, is significantly smaller, measuring between 23-35 mm. It prefers damp environments and hides in dark corners, under doors, and in cracks. Females can produce 12-30 egg capsules in their lifetime, each containing up to 24 eggs. They mature in 12 months and live for about eight months. They are often found near food and water sources indoors.
Oriental Cockroach (Blatta orientalis): Also known as the “black beetle” due to its dark brown colour, this cockroach measures around 20-25 mm. Males are smaller with large wings, while females are larger with no wings. They inhabit wet areas and are highly adaptable. Females produce 16 eggs per egg casing, which hatch in about two months. Adults live for about six months on average.
German Cockroach (Blatella germanica): Identified by two dark stripes around its head, this cockroach is smaller and faster than others on this list, measuring only 13-16 mm. They prefer to live indoors in dark, damp environments and are often found where food is stored. Females carry their egg casings for 30 days until the 35-40 eggs inside are ready to hatch. Their life cycle lasts about 100 days, and they can produce three to four generations per year.
American Cockroach (Periplaneta americana): The largest common pest species, measuring 35-40 mm, these cockroaches are reddish-brown with a pale yellow line around the upper thorax and pale legs. They prefer to live outside in warmer months but will invade homes for food and water. Females can produce up to 50 large egg capsules in their lifetime, each holding 12 to 16 eggs.
Brown Banded Cockroach (Supella longipalpa): Measuring about 10-15 mm, these cockroaches have a pale, glossy brown colour with very pale streaks running down the thorax and abdomen. They prefer warmer buildings and appliances and are often moved in furniture, luggage, and other household items. Females produce approximately 14 egg capsules in their lifetime, each containing 10-18 eggs.
Smoky Brown Cockroach (Periplaneta fuliginosa): As their name suggests, these cockroaches are a smoky brown colour. They’re quite large, measuring 35-40 mm in length. They prefer to be outside in enclosed, warm, humid environments, such as sheds. Females lay 22-26 eggs in an egg casing in a dark place to hatch.
To deal with cockroaches, a thorough inspection, reduction of food, water, and shelter supplies, and extensive use of insecticides or baits are all necessary for effective pest management. The first step is to locate the nest, which is usually in a dark, vibration-free environment. Cockroach droppings may be visible around the nest’s location, or you can use your nose to sniff it out—most cockroach nests have a strong, unpleasant odour.
