The Australian cockroach, scientifically known as Periplaneta australasiae, is a peridomestic species of cockroach that is similar in appearance to the American cockroach. It lives predominantly outdoor but occasionally infests homes. In the United States, this species is often found in the southeastern states like Florida.
• Australian cockroach
• Shade roach
• Palmetto bug (in Florida) (This common name is also used for other species)
Morphology of the Australian Cockroach
The Australian roach is smaller than the American cockroach but shares similar characteristics. It has a reddish-brown to dark brown coloration with yellow markings on the tegmina (on the top of the head). The obvious difference with the American cockroach is the presence of light yellow markings on the upper margin of the forewings. This species can also be recognized by the presence of yellow stripes on the edge of the wings. The size of this Australian species is roughly 23 to 35 mm in length. Adults wing fold completely over the abdomen.
Behavior and Diet of Periplaneta australasiae
Australian cockroach is peridomestic and thus lives mostly outside around houses. They live primarily under tree barks, and in piles of firewood. The nymphs can often be seen feeding in group. Sometimes they move in human dwellings and are found under sinks, in toilets, garbage cans, kitchens, attics and other dark areas. Their primary food is of plant origin and other decaying materials. Inside buildings, they may feed on any food source they come across but they tend to prefer starchy food source including book bindings as well as clothes. Both male and females of this species can fly. The nymph usually feed in group. It is often difficult to distinguish the male and the female. The only obvious difference is through genitalia. This species of cockroach can run quickly when sighted. The Australian cockroach has a wide variety of food source most of which being decaying organic matter.
Life Cycle of the Australian Cockroach
Like all other cockroaches, this species undergo 3 developmental stages including eggs, nymphs, and adults. They have 5 different nymphal instars that gradually develop into adults of palmetto bug. It takes approximately one year for the female to become mature and sexually active. Typically 20 to 30 oothecae (egg cases), each containing in average 24 embryos, are produced by a single female during her lifetime. The female of this species carries their ootheca with them but deposited them long before the eggs hatch. It takes about 40 days for the embryos to fully develop into nymphs, which take one year to mature into sexually active adults. The nymphs have a light yellow spot on top of their abdomens and this characteristic is often used to distinguish them from the nymphs of other species. The Australian cockroach prefers warmer climate and is incapable of thriving in cold climate.
Distribution and Habitat of the Australian Cockroach
Despite its name this cockroach species can be found in many parts of the world. It is believed that roach species originated from Africa and was introduced into Australia. It may have been introduced in the Americas during the fifteen century’s slave trade. In the United States, the Australian cockroach is mainly found in the Southern States like Florida, Alabama, Mississippi and Louisiana but it can also be found in the northern states. It is often more competitive than the smokybrown cockroach in areas where they both species occur. Periplaneta australasiae is often found in greenhouses where it can cause severe damage to seedlings. This roach can also be found in crack and crevices in apartment buildings.
Prevention of Australian Cockroach Infestation
Infestation by this species is relatively easy to prevent since it lives mostly outside. Best practices include sealing any cracks and crevices to prevent entry into buildings. Windows and doors should also be equipped with tight screens to prevent entry. It is also important to eliminate any food sources that are outside. For instance pet, food should not be stored outside as this can be the source of food for this species. This cockroach feed on plant material, so if you use firewood to make sure you don’t keep them for a long time as they can provide safe heaven and breeding ground for the Australian cockroach.
Control of Australian Cockroach
In general, control of Periplaneta australasiae once established, rely on insecticide sprays to exterminate the population. There are currently a number of products on the market that can be used for extermination. For instance, one product that is very effective against the Australian cockroach is the LambdaStar Cap Ultra 9.7, Defense SC Cyper WSP. This product has no smell and has long-lasting activity against cockroaches. You can spray it both indoor and outdoor. It is always recommended to follow the instructions on the product label. Roach bait can also be used to exterminate the large population of this roach.