Bush cockroaches fact sheet | Field of Mars EEC

What are bush cockroaches?

Bush cockroaches are harmless, native cockroaches, not the pest species you find in your home! Australia has over 500 species of native cockroaches that live in the bush.

Bush cockroaches, along with all other cockroaches, belong to a group of  insects  called Blattodea.  Blatta  is the Greek word for cockroach.

Bush cockroaches come in a range of shapes and sizes. The smallest species is around 3 millimetres long, whilst the largest, the giant burrowing cockroach, grows up to 8 centimetres long and weighs up to 20 grams.

Most bush cockroach species are nocturnal, meaning they are active at night time.

This illustration represents most of the bush cockroaches found in the Field of Mars Reserve.

Mitchell’s diurnal cockroach – Polyzosteria mitchelli –is one of the most colourful species of bush cockroach.

Where do bush cockroaches live?

Bush cockroaches are terrestrial, meaning they live on land. They can be found in the mulch or leaf litter layer.  Some species of native cockroaches are found only in caves. These cockroaches are pale, blind and have no wings.

Nocturnal species of bush cockroaches that are only active at night hide during the day to protect themselves from predators. Most bush cockroaches hide under bark, logs and stones. Some species of bush cockroaches hide in burrows they create underground or in rotting logs. Burrowing cockroaches can dig burrows up to one metre deep.

Many cockroaches such as this species – Polyzosteria fulgens – have hooks on their legs which help them to dig into the soil and cling onto surfaces.

What do bush cockroaches eat?

Most bush cockroaches forage for food on or near the ground. Many species of bush cockroaches are important decomposers in their ecosystems as they eat rotting leaves and wood and excrete fertiliser which can be used by plants.

Some species of bush cockroaches feed in trees, eating pollen, bark and leaves. Other species have special guts that allow them to eat wood, much like termites.

Most bush cockroaches are nocturnal and forage for food at night.

Cockroaches such as the desert racing cockroach play an important role in the leaf litter layer.

What eats bush cockroaches?

Bush cockroaches play an important role in the ecosystem as food for large invertebrates, mammals, frogs and reptiles.

To avoid becoming food, some bush cockroach species ward off their predators by hissing and producing a pungent smell.

Giant burrowing cockroaches hiss when threatened.

How do bush cockroaches reproduce?

Bush cockroaches have two ways of producing young. Whilst most species lay eggs, others give birth to live young through a process called ovoviviparity. This involves eggs hatching inside the body of the mother and being laid as live young.

Some species live as families with parents feeding and caring for their young for up to nine months.

Cockroaches lay an ootheca, which is a mass of eggs surrounded by a hard, protective case.

What is the life cycle of the bush cockroach?

Bush cockroaches grow and develop through a process called incomplete metamorphosis. The time it takes for bush cockroaches to complete this process depends on the species.

Juvenile bush cockroaches, called nymphs, often look like adults, with some variation in colour or texture. Some also lack wings.

Egg

Bush cockroaches begin their life as an egg.

A cockroach egg case – ootheca

Nymph

When bush cockroaches hatch from their eggs they are called nymphs.

In order to grow or change shape bush cockroaches must shed their hard exoskeleton. Bush cockroaches undergo numerous moults before becoming adults.

A cockroach nymph

Adult

Compared to insects bush cockroaches are relatively long-lived. Some species such as the giant burrowing cockroach can live up to 10 years.

An adult cockroach

Related fact sheets

More invertebrate fact sheets

• Invertebrate fact sheets – overview
• Insects fact sheet – explains insect features and how cockroaches fit into the insect group.
• Myriapod fact sheet (many-segmented invertebrates like centipedes and millipedes)
• Gastropod fact sheet (slugs and snails that also live in moist soil and leaf litter)

Habitats and ecosystems

• Leaf litter habitat fact sheet
• Field of Mars Reserve fact sheet

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