Australian Cockroach: Facts, Behavior, Life Cycle, Infestation, and Identification

Last Updated on April 30, 2021 by Kimberly Crawford

The Australian cockroach is one of the eight most common types of cockroaches.

They are considered as peridomestic which means that while their natural habitats are outdoors, they could cause roach infestation in the house when they take shelter during extreme temperatures or when they find that your homes have a steady reserve of food and safe refuge.

If you are suspecting probable Australian cockroach infestation in your home or want to be enlightened about specific types of cockroaches, we will cover all the essentials in this post for you. 

Australian cockroach facts

Before we go to the specifics, here are some Australian cockroach facts that you must know about. 

  • The Australian cockroach completes its full life cycle in just a year. This is comparable to the German and American cockroach life cycle. 
  • They are not natives to Australia, contrary to what the name implies. They are native to Asia and are considered as notorious contaminators in the kitchen during summer. 
  • These species produce 20-30 eggs and will hatch at least 16 molts out of this
  • They are considered as the most prevalent roach type in Florida. 
  • They are found more in the landscape area and stable water sources around the house’s perimeter. 


Australian cockroach size


The first thing to prevent an infestation is always identification. As have been said, even if they stay outside the house, Australian cockroaches stay around the perimeters, lurking around until a trigger pushes them to go inside. Here are the characteristics of the Australian cockroach that you must spot. 


Adult Australian cockroaches have a reddish-brown to dark brown color with yellow margins along the thorax and have yellow stripes on their wings. Nymphs, on the other hand, start off as dark brown to black with paler brown spots and the yellow margin on the thorax. 


Female and male Australian cockroaches have a slight size difference. Males are larger than females with a length of 35mm while females are at just 30mm. 


Differences between male and female roaches of this type is still the focus when it comes to appearance. To distinguish them, you have to look for the appendages in the dorsal area.

Male Australian roaches typically have two appendages while females only have one. Most importantly, only female roaches of this type have abdominal plates.  


They are nocturnal and agile fliers in canopies of trees and other vegetation. Once they have entered your home, they would leave egg casings around since they are prolific when it comes to reproduction.

You will find that most of these casings will be concentrated in bathrooms and the kitchen after they have hatched. They are hard to spot and most of the time because the mother Australian roach would camouflage them in hidden locations. 

Where will I find Australian cockroaches in my home?

When it comes to the indoor refuge, Australian cockroaches will be found in locations near water and food supply.

As such, you would find them niching in sinks, bathtubs, beneath your furniture, cabinets, pantry, storage areas (including boxes and old cartons), drains, and also in water pipes. 

History and distribution

The name Australian cockroach was given to this roach species because it has become the most endemic cockroach type in the early 1900s. Its entomological history is traced back to South Asia.

The distribution is said to have been facilitated by docks and cargo shipments at the height of colonialism. The current distribution of Australian roaches includes the southern US states where the climate is ideal for them to thrive. 

Habitat, the biology of Australian Cockroaches


They are winged fliers with a length of 0.5 to 1inch. They are different from American roaches in terms of color as they have yellow spots and yellow stripes along the back and wings.

They thrive in humid and hot climates and are known vegetarians eating clothing, paper, and young plants. They have a 12-20-month life cycle including the egg stage, five nymph stages, and adulthood. 


They are mostly found in places near seaports, docks, and shipping areas. In the home, you would find colonies of them in spots where it is hot, humid, and moist.

Specifically, you would find them in greenhouses, heated fish tanks, attics, and other crawl spaces where they could sprawl. 


Australian cockroaches love heat and high humidity locations. Any tropical or subtropical climate region is prone to these roaches. But in time, they have evolved and they could easily find their way into your homes especially if you offer them a steady food supply and good hiding spots to thrive in. 

Diet of Australian Roaches

For one, they are also called greenhouse roaches because they could munch on very young plants. Outdoors, they munch on bark, decomposing organic matter, piles of leaves, and more. Indoors, it would feast on anything from crumbs, paper, items in the garbage can and all. 

How to identify Australian Cockroaches

australian cockroach 2

They could be easily mistaken for American roaches because they are almost similar in size and appearance. The only identifying factor would be the yellow lines on their bodies and the yellow stripes in their wings particularly in the front edges. 

Australian cockroach Life cycle

Australian cockroaches’ lifespan lasts for a year to almost two years. Females will successfully produce 16-24 ootheca from 30-40 eggs every 10 days. It will take 30-40 days before the eggs hatch and bring out molts.

Australian cockroach nymphs spend six to twelve months on this stage before reaching adulthood. The adult Australian cockroach spends eight months before it dies.

Australian cockroach baby

Like all other roaches, Australian cockroach babies are technically called nymphs. Unlike adults, they are wingless. They have dark brown to a black color and they will have visible yellow spots scattered along their backs.

These yellow patches will become more prominent as they enter adulthood and their colors will turn to reddish-brown. 

Australian cockroach eggs

Cockroach eggs in general are laid in humid and damp locations. Indoors, the eggs could be found in storage rooms, kitchens, and bathrooms.

Australian roaches lay 30-40 eggs every 10days. Each egg contains 16-24 viable nymphs. Each egg starts as white. For the next few weeks, it will harden and become reddish-brown in color, ridged on the edges, and is about a quarter of an inch long. 

Australian cockroach species

If the question is about are there other roach species belonging to the Australian roach type, the answer is none. Roaches are not like plants and some animals.

You would find that they have different scientific names although they are all roaches. But if the question is about how many species of roaches are found in Australia, then we can tell you that 400 recognized roach species could be found and are endemic in the country. 

Signs of Australian cockroaches

The first sign of Australian roaches would be seeing them run along to hide. And since they are fast runners, you would not catch them right away.

To spot where they have been running along, you can look for egg casings and droppings. But the easiest way to look for Australian roach signs is to find yellow markings which only they could leave.

Occasionally finding them in sinks, tubs and cabinets are also signs of probable infestation. 

How to get rid Australian cockroaches quickly

There are two ways to get rid of roaches quickly. One is using natural methods which by the way, are basic sanitation pointers that are easy to master and two is the chemical method which includes granular, baits, and insecticides. 

Chemical methods

Get rid of Australian cockroaches

If you want the easy riddance, you can always opt for chemical methods. Here are what you can use chemically and how they will function. 


This is the perimeter barrier intervention. It has to be applied in probable access points such as doors, windowsills and gaps, sinks, pipes, and plumbing. 


This one is applied where garden mulches are stored, straw stocks, and around the house’s perimeter. 


If you spot them and they have become larger, you can put baits in overhung gutters, on access points in the house, and also in turf areas. 

Natural methods

If you feel like you would be more comfortable using natural methods, here are some pointers that you should master. 

Exclusion procedures

  • Seal cracks and gaps around and inside the home using putty, wood, plastic, or caulking compound. 
  • Make sure that windows, doors, and screens are tightly shut. 
  • Do not pile up firewood and empty boxes around and inside the home.
  • If possible, provide ample ventilation in moist spaces in the home.   

Sanitation pointers

  • Do not pile up pet food outdoors. 
  • When you vacuum, empty the dirt box immediately. 
  • Clean window sills and access points regularly. Remove rotting leaves if there are any. 
  • Stop water leaks early on. 
  • Keep garbage cans tightly shut and move them in locations where moisture cannot penetrate. 
  • Keeping minty humidifiers on is a plus. 

Tips for prevention of Australian roaches

To manage the probable infestation, an ounce of prevention is still better than cure. Here are some prevention tips that you should know of to seal off those roaches before they could even reach your home. 

  • Install vent screens. 
  • Seal up crevices and cracks around the house’s perimeter. Apply more on the house’s foundation. 
  • Secure garbage cans with tight shuts and away from moist locations. 
  • Keep off the possible food supply in patios and decks. 
  • Keep everything clean. 

Frequently Asked Questions

Are Australian cockroaches harmful?

It is safe to say that all types of common cockroaches post a danger. They niche outdoors and are carriers of bacteria and germs that will contaminate the places they walk on.

And if they found your home, you might be exposed to almost 33 types of germs and bacteria including E.coli and salmonella. Their egg casings are also allergens. They could trigger sneezing and asthma episodes. 

They could also munch on young vegetation, hence, their nickname greenhouse roaches. While they would not make them a steady food supply, they could harm your young plants. 

What do Australian cockroaches eat?

Strikingly, Australian cockroaches are the only peridomestic roach type that is considered vegetarian. We have mentioned here that they eat plants. Specifically, they munch on young plants. This is why they are also called greenhouse roaches. They also occasionally munch on tree barks in the outdoors. 

On a more extreme note, like other cockroaches, they also feed on decomposing matter, garbage, crumbs in the kitchen, and even fecal matter. This is why, as friendly-looking as they may seem compared to American and German roaches, they pose threats of food contamination especially if they are already living with you in your home. 

What is the difference between Australian cockroaches and American cockroaches?

In terms of size, they are fairly similar. They both grow long at 0.5 to 1.5 inches. There are two main differences between these two roach types though.

One, American roaches are more prolific when it comes to reproduction and have shorter lifespans.

Two, both have a reddish-brown to dark brown color but Australian roaches have yellow streaks and yellow stripes in the wings’ edges. 

Can Australian roaches fly?

Yes. Australian roaches have fully developed wings that will allow them to glide and fly (but not too high and not too far). Unlike smoky brown roaches, they are not attracted to lights. So basically, they use their wings to take a flight out of danger or from being startled and in securing food. 


To conclude, the Australian cockroach is just one of the eight types of peridomestic roaches that pose threats of infestation. But it is striking to note that this roach type has some pretty interesting character traits compared to other types.

One is that they munch on young plants, hence, the name greenhouse roach.

Two, they have longer lifespans compared to German and American roaches which by the way looks similar to it in terms of size and appearance. All in all, Australian roaches are interesting on their own but then again, since they are still dangerous, they must be properly studied.