Cockroaches are survivors from around 300 million years ago. They are one of the longest surviving arthropods on the planet and it is estimated that they have now developed into more than 36,000 species variations although very few – maybe only six – are considered as domestic and commercial pests. A decapitated cockroach can survive for up to 72 hours.
All cockroaches have flat bodies, enabling them to hide under bark, in crevices and run under doors. Their six legs are almost even in length and the antennae are long. They begin their lives as eggs that hatch into a flightless larva which shed their skins several times as they grow. Adults also cast their skins, develop wings and can live for up to 3 years. Although they have wings, adult cockroaches are more likely to run than fly which, along with their size and speed, makes them a genuine creepy crawly.
The eggs are carried by the female in a capsule and hatching larvae grow through a series of between 5 and 12 moults. The larger species become adults in 9-12 months but the German cockroach can mature in 40 days and, with up to 40 eggs in a capsule, the ‘family’ could number 20,000 in a year.
The main pest species in Australia are:
Adults are 20-25mm in length and honey coloured. German cockroaches prefer warm kitchens or storerooms inside buildings.
Adults can grow up to 55mm and are deep red/brown in colour. Americans prefer moist areas, both inside and outside and can readily flies in warm climates.
There are hundreds of species, mostly found in gardens, but these are not generally considered as pests.
All cockroaches avoid light and prefer warm, moist situations close to a food source. Their indiscriminate feeding in such areas as sewers, drains and garbage areas brings them in contact with disease organisms associated with dysentery, typhoid, hepatitis and tuberculosis. Cockroaches are also known to produce allergic reactions in humans and, in some instances, severe asthma attacks.