Cockroaches are often overlooked for their stunning patterns and vibrant colours, but did you know that only 1 percent of cockroach species worldwide actually transmit disease?
While the mere mention of 'cockroach' might evoke disgust, it’s important to remember that this reaction is directed at just a small handful (less than seven species) out of the approximately 4,500 species of cockroaches around the world, occurring in every Australian habitat except lakes and oceans.
Cockroaches are essential to the Australian outdoors, playing crucial roles as decomposers, chewing through dead organic material (animals and plants) and being a key food source for other animals.
Australia is also home to the world’s heaviest cockroach – the Giant Burrowing Cockroach, weighing up to 35g!
(Image: Charlotte Raven)
These amazing critters give birth to live young, exhibit year-long parental care, and are even sold as pets.
Growing up, I had three Giant Burrowing Cockroaches as pets, which I largely attribute to my passion and amazement for Australian cockroaches.
Though Australian native cockroaches cannot live with humans or inside homes (they are dependent on specific habitat types), cosmopolitan cockroaches are understandably unwanted visitors in our homes.
While I am emphasising the importance of our Australian native roaches, the invasives we find in our homes can pose a level of risk to humans.
(Image: François Brassard)
Are cockroaches dangerous and can they bite?
Cockroaches don’t have teeth, nor do they have a mouth that is designed to ‘bite’ like that of a spider.
Their mouth parts are designed to chew and ‘scrape’ food, and when in our home, they are often feeding on our food and rubbish.
Despite their lack of ‘biting’ ability, some cases have been recorded where American cockroaches have nibbled on a finger, leaving a minor wound, usually no more than 2mm in length – although it’s important to note that this person went to sleep with food on their fingers.
Regardless, the risk cockroaches pose doesn’t come from their appetite for crumb flavoured fingers, but from their ability to transmit disease by carrying pathogens on their bodies in our homes.
People with asthma and other respiratory issues can be triggered by cockroaches due to specific proteins found in their saliva, droppings and bodies.
It is important to note however, that these risks are from pest cockroaches we get in our homes, rather than the native cockroaches we see outside in nature.
(Image: Evelyn Virens)
How to get rid of cockroaches?
Getting rid of cockroaches requires a combination of cleanliness, exclusion, and targeted control methods.
Start by removing their food, water and shelter sources—store food in sealed containers, clean up crumbs, fix leaky pipes and declutter spaces where they could hide.
Seal cracks, gaps, and crevices in walls, doors and windows to block entry points.
For more persistent infestations, traps, baits and insecticides can be effective, but it’s crucial to use these products as directed to ensure safety.
As for the common belief that coffee grounds deter cockroaches, while some anecdotal evidence supports this, scientific research hasn’t confirmed it as a reliable deterrent.
Interestingly, cockroaches may even be attracted to the grounds when wet, as they seek out organic materials to feed on.
Instead of relying on coffee grounds, it’s best to focus on proven methods of prevention and control to keep these resilient pests at bay.
Can cockroaches fly?
Yes, some cockroach species can fly, but it’s far from their primary mode of transportation.
While most adult cockroaches have wings, their flying abilities vary greatly.
Some, like the American cockroach, can fly short distances when escaping predators or seeking higher ground, while others, such as the Australian cockroach, are more adept fliers.
However, many common pests, like the German cockroach rarely use their wings at all, relying instead on their impressive speed on the ground.
Interestingly, wings also play a role in cockroach courtship behaviours. Female cockroaches chemically ‘call’ males by arching their bodies or lifting their wings, releasing pheromones to signal readiness for mating.
In some species, the males reverse the roles, raising their wings to release their own pheromones and attract females.
(Image: Gunter Maywald)
Are cockroaches clean?
It might surprise you, but cockroaches themselves are actually meticulous groomers. They spend a significant amount of time cleaning their antennae and bodies to maintain sensory sharpness, which is crucial for detecting food, predators and mates.
However, their cleanliness stops at their own hygiene.
Cosmopolitan cockroaches often inhabit some of the dirtiest environments, such as garbage bins, drains and decaying matter, which makes them effective carriers of bacteria and pathogens.
As they crawl across these surfaces, they pick up germs on their legs and bodies and can transfer them to food, countertops and other areas in our homes.
In this way, while they are individually ‘clean’ by their standards, their behaviour and habitat expose humans to health risks.
Interestingly, researchers have discovered that a parasitic wasp can inject a chemical, such as dopamine or a mimic, into a cockroach's brain. This manipulation increases the cockroach's antennal grooming, likely due to changes in its brain!
Nevertheless, to minimise cockroach-related risks, maintaining a clean environment and addressing potential infestation sites is key.
Remember, the cleaner your space, the less attractive it becomes to these uninvited guests (and surely more attractive to your invited dinner guests).
(Image: François Brassard)
What attracts cockroaches?
Cockroaches are incredibly resilient, rooted in their ability to adapt and find the basic resources they need: food, water and shelter.
They can consume almost anything, from crumbs and leftover food to less conventional items like paper, glue and soap.
Cockroaches are highly attracted to moisture sources such as leaky pipes, standing water and damp surfaces. In fact, they can survive for weeks without food, but only days without water.
This need for moisture explains why they are often found in kitchens and bathrooms.
Cockroaches also prefer warm, dark, and sheltered environments, which is why they often gravitate toward the hidden corners of homes, and under debris.
While we can recognise the damage posed by invasive cockroaches in our homes, it’s important to appreciate the vital roles that native cockroaches play.
So, next time you encounter one, remember, not all are pests, and many deserve our respect and awe for the roles they play in keeping our environment healthy.
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