Australian Cockroach Species

There are around 4,000 species of cockroaches worldwide and about 450 species in Australia, but very few are pests.

The three main types of cockroaches commonly found in homes and businesses in Australia include the German cockroach, Australian cockroach and American cockroach.

Identifying the cockroach species will help deal with an infestation more effectively. See below for descriptions of the appearance, lifestyle and habits of the cockroaches common in Australia:

Australian Cockroach

(Periplaneta australasiae)

Lifecycle

  • Females deposit the ootheca (egg case) containing 24 eggs a day after production.
  • After hatching nymphs take 6-12 months to develop into adults.
Habits of the Australian cockroach

Habits

  • Enter buildings at night from gardens/debris.
  • Generally prevalent in areas where winters are relatively mild.
  • Despite its name, it isn’t a native species.

German Cockroach

(Blatella germanica)

German Cockroach

Appearance

Notorious for their world-wide distribution, German cockroaches are easily identifiable by 2 dark longitudinal stripes on their pronotum. Adults grow to approximately 12 – 15mm in length.

Lifecycle and habits of the German cockroach

Lifecycle

  • Females carry 35 – 40 eggs in an ootheca (egg case) until they are ready to hatch.
  • Hatch in 1 month.
  • Nymphs take between 6 weeks to 6 months to develop into adults.
  • Generally 3-4 generations per year.

Habits

  • Most commonly found indoors.
  • Prefers wet, humid conditions and are typically found in kitchens and bathrooms in homes and commercial properties.

Oriental Cockroach

(Blatta orientalis)

Oriental cockroach

Appearance

  • Dark brown or black in colour.
  • 20 -25mm long.
  • The wings undeveloped in female and cover ¾ length of the abdomen in the male.
Lifecycle and habits of the oriental cockroach

Lifecycle

  • Females deposit 16 eggs in an ootheca (egg case).
  • Hatch in 2 months.
  • Nymphs take 6-18 months to develop into adults.

Habits

  • Highly adapted for surviving in the natural environment, Oriental cockroaches thrive in cool, damp areas such as basements, drains and openings beneath porches.
  • Known for their preference for feeding on garbage and decay, these insects can most commonly be found in rubbish tips and leaf litters.
  • Runs rather than flies.

American Cockroach

(Periplaneta americana)

The American cockroach is one of the largest pest cockroaches to invade homes and commercial properties.

American cockroach

Appearance

  • 35 - 40mm long.
  • Shining red–brown in color.
  • Wings longer than the body in male; only just overlap abdomen in female.
  • Runs (may fly at very high temperatures).
Lifecycle and habits of the American cockroach

Lifecycle

  • The ootheca (egg case) containing up to 16 eggs is carried by the female for several days before being deposited. Sometimes cemented down and tend to be grouped.
  • Hatch in 1 – 2 months.
  • Nymphs usually develop in 6 -12 months, but it can take up to 15 months.

Habits

Also known as the ‘Palmetto bug’ because they live on trees, the American cockroach prefers dark, humid and undisturbed areas and can be found in subfloors, basements, kitchens, roof voids and bathrooms of homes.

Brown Banded Cockroach

(Supella longipalpa)

Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Appearance

One of the smallest pest cockroaches, brown banded adult cockroaches are approximately 10 – 15mm in length and characterised by yellow-brown stripes across their abdomen.

Habits of the brown banded cockroach

Habits

Brown banded cockroaches mostly stay on ground, but may fly in very warm climates. Their preference for warm, humid environments leads them to harbourages within heated buildings - ceilings, attics, inside and around appliance motors. Primarily active at night, these opportunistic feeders particularly enjoy materials with high starch contents.

Smoky Brown Cockroach

(Periplaneta fuliginosa)

Appearance

  • 3-35 mm mm long.
  • Shining dark brown in colour.
  • Wings longer than the body in male; only just overlap abdomen in female.
  • Runs (may fly at very high temperatures).
Lifecycle and habits of the smoky brown cockroach

Lifecycle

  • Females deposit the ootheca (egg case) containing 22-26 eggs a day after production.
  • Nymphs take between 6-12 months to develop into adults.
  • The noticeable difference between nymphs and adults, apart from size, is the lack of wings in the young.

Habits

  • Lives in tree hollows, under bark, under floors, and enters buildings at night.
  • Nocturnal (hides during the day in cracks and crevices or any other dark warm places).
  • Has a habit of entering houses and contaminating food with excrement, regurgitated salivary fluid and potentially harmful bacteria.