Cockroaches - Annoying Pests, Interesting Pets and Useful Robots

A side view of an American cockroach, or Periplaneta americana
A side view of an American cockroach, or Periplaneta americana | Source

Cockroaches in North America are generally detested and even feared animals. I can certainly understand these feelings. They are interesting insects, though. Most cockroach species in the world are not pests. At least one - the Madagascar hissing cockroach - is kept as a pet. Even pest cockroaches can be useful. Their movement has inspired the creation of cockroach robots that can move quickly over a wide variety of terrain. Living cockroach robots are also being created.

Most of the approximately 4,500 species of cockroaches on Earth live in warm and moist tropical and subtropical forests. Only a small number of cockroach are pests, but these species can be a serious nuisance and cause health problems.

The upper surface of an American cockroach
The upper surface of an American cockroach | Source

Cockroach Bodies

Cockroaches have flat and oval bodies with long, flexible antennae. Like other insects, they have three pairs of legs. The antennae are sensitive to touch and smell. The legs have spines. Cockroaches are generally between half an inch and two inches long. North American roaches are brown or black, but some tropical cockroaches are attractive animals that are green or yellow in colour.

Cockroaches have two pairs of wings. The outer, leathery pair hides the inner, membranous wings. Some roaches can fly, but not all of them can. They don’t breathe through their mouths but absorb air through holes called spiracles on the side of their bodies. The spiracles lead to tubes called trachea inside the roach’s body, which transport oxygen to where it’s needed. The legs of a cockroach move quickly. The insects travel at a speed of about one to two feet a second. Bigger roaches may move even faster.

A German cockroach has two dark stripes behind its head.
A German cockroach has two dark stripes behind its head. | Source

Successful Pests

In North America, four common pest species are the American cockroach, the Oriental cockroach, the Brown-banded cockroach and the German cockroach. The German cockroach (Blattella germanica) is usually the most common pest cockroach in many parts of the world and is the most troublesome. It’s brown in colour and has two dark stripes behind its head.

Roaches can be found in humid areas like bathrooms and kitchens. They also live in basements, garages and gardens. Cockroaches are nocturnal creatures. During the day they hide in dark places, such as cracks, drawers and cupboards. They also hide in spaces behind pictures and wall clocks, in heating ducts and in areas around plumbing and sewage pipes. In addition, they may be discovered in drains, under sinks and behind stoves and refrigerators, especially near the refrigerator’s motor.

Cockroaches eat a wide variety of materials. This factor has contributed to their pest status. They eat both human and pet food. They also eat garbage, plants, the glue in book bindings or on the back of postage stamps, soap, toothpaste, paper and fabric.

Roaches quickly run for cover if the light is turned on when they're in an open space. They have two antennae-like extensions called cerci at the end of their abdomen. The cerci are very sensitive to air currents, including those created by someone trying to sneak up on the insects.

The outer covering of a 40 to 50 million year old cockroach preserved in amber
The outer covering of a 40 to 50 million year old cockroach preserved in amber | Source

Cockroaches and Human Health

Some cockroaches – such as the American cockroach - may come into contact with human feces in sewers and with pet feces. If they then walk over human food they may contaminate it with bacteria, including the species of Salmonella and Shigella that cause food poisoning. In addition, roaches deposit their saliva and feces in our food. German cockroaches are also believed to transmit bacteria and viruses, including organisms that cause hepatitis, typhoid fever, dysentery and gastrointestinal disorders.

As cockroaches move, they leave a trail of feces containing chemicals that communicate messages to other cockroaches. These messages include the route that the cockroach is taking to find food or water. The fecal trails may appear as dark stains or black specks. Cockroaches also release smelly secretions that can affect the flavour of foods and fill the air with an unpleasant odour when a large number of roaches are present.

Cockroach feces, saliva and secretions can cause allergies and asthma in humans. The body coverings that roaches shed when they molt and their empty egg capsules can also trigger allergies.

A Cockroach Infestation

Some Interesting Facts About Cockroaches

  • Cockroaches can survive for one to two weeks without drinking and up to a month without food.
  • Some cockroaches have survived for forty minutes without air.
  • A cockroach can survive without a head for a week. The brain is located in the head, but there are ganglia - collections of nerve cell bodies – in other parts of the body. These ganglia are responsible for a lot of a roach’s activities.
  • A headless roach dies of thirst, since without its head it can’t drink.
  • Each of a cockroach’s eyes is made of 2000 lenses, compared to the single lens in a human eye.
  • The legend is that in a nuclear war only cockroaches would survive, since they are resistant to radiation. Experiments have shown that cockroaches are about six to fifteen times more resistant to radiation than humans. Some insects – such as fruit flies - are much more resistant to radiation than roaches, however.

An ootheca, or egg capsule, being laid by a female Periplaneta fuliginosa
An ootheca, or egg capsule, being laid by a female Periplaneta fuliginosa | Source

Cockroach Reproduction

Cockroaches of the opposite sex attract each other at mating time by releasing chemicals called pheromones. Usually the female produces pheromones to attract the male. In some species, the male produces a pheromone from glands on his back, which the female eats.

After mating, most female cockroaches produce an egg capsule, called an ootheca, which the female carries around under her body at the end of her abdomen. The ootheca is usually dropped shortly before the eggs hatch. The egg capsule contains from twelve to sixty eggs.

The hatched young are called nymphs. They are white at first but turn brown within a few hours. They look like miniature adults except for their undeveloped wings. The young take one to four months to develop into full-sized adults. An adult female may produce up to eight egg capsules in her lifetime, which is up to a year for the German cockroach.

Madagascar hissing cockroaches are kept as pets.
Madagascar hissing cockroaches are kept as pets. | Source

Madagascar Hissing Cockroaches

The Madagascar hissing cockroach, or Gromphadorhina portentosa, is often kept as a pet. It's a large and wingless cockroach with an oval body that reaches two to four inches in length. The roach is an attractive insect with a shiny appearance. It's brown in colour and has dark red or tan patches.

The hissing cockroach is one of the many fascinating animals that live in Madagascar. In its natural habitat, the insect eats fruit and other plant parts on the forest floor and is not a pest. It's mainly nocturnal but may be seen in the day. The roaches live in colonies headed by a male, who actively defends his territory against the intrusion of other males.

Although the hissing cockroach can't fly, it has special pads on its feet that allow it to climb on a wide variety of surfaces. The pads are hooked. Anyone wanting to keep the cockroach as a pet should keep its ability to climb in mind.

The Hissing Cockroach

Horns and Hisses

The male hissing cockroach has a pair of protuberances behind his head. These are often referred to as horns. The cockroach uses his horns to ram into another male during a fight. The female has horns too, but they are much smaller than the male's.

The cockroach makes a hissing sound by exhaling air through a pair of special spiracles on its abdomen. The sound is made during courtship and during interactions between males. It's also used to scare predators.

Cheesestain, a pet Magagascar hissing cockroach, giving birth
Cheesestain, a pet Magagascar hissing cockroach, giving birth | Source

Hissing Cockroach Reproduction

The reproduction process of the hissing cockroach is unusual compared to that in North American cockroaches. The animal is ovoviparous, which means that the eggs in the ootheca hatch within the female's body. The young are then born live.

The cockroach gIves birth to thirty to sixty babies. These are white in colour and are known as nymphs. The nymphs take five to seven months to mature, molting and darkening in colour as they grow. The cockroach can live for two to five years.

Pet Madagascar hissing cockroaches
Pet Madagascar hissing cockroaches | Source

Cockroach Robots

Scientists are creating robots that move like cockroaches. Their goal is to create robots that can run rapidly over varied terrain and change direction quickly, just like real cockroaches do. The robots could be sent into areas which are too difficult or too dangerous for humans to travel though. They could also send messages to humans if they have the right equipment. Scientists even envision cockroach-like robots that could communicate wirelessly with each other, forming a network.

European scientists have created a robot cockroach that mimics some aspects of a cockroach’s behavior and is accepted by cockroaches once it's covered by cockroach pheromone. The scientists found that cockroaches follow the robot, even moving from the dark into the light, an abnormal behavior for most cockroaches. Scientists are using the robot to study the behaviour of cockroaches when they are in groups. The robot may one day be used to control roach populations.

Living Cockroach Robots

Hybrid Living Cockroach Robots

In a recent development, scientists have begun the process of creating living cockroach robots. They've attached robotic devices to the backs of cockroaches. These devices connect to the nervous system of the roach. The goal is to control the cockroach's legs to force the roach to go where we want. The researchers are already having some success with this goal.

The research into creating "robo-roaches" is certainly interesting, but I find it worrying as welI. I don't expect that many people will complain about cruelty to roaches. The technology has also been used to create remote-controlled rats, however. Rats are intelligent and sentient creatures. The future development of the technology concerns me. It could certainly have benefits, but it could also be used inappropriately.

Cockroaches - More Than Just a Pest

Scientists believe that cockroaches have lived on Earth for about 320 million years, with little change in their bodies. They are very successful creatures. The pest species can certainly be annoying and are understandably hated by some people. There is so much more to cockroaches than the ability of a few species to act as pests, though. They are fascinating animals.

© 2010 Linda Crampton

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Comments 18 comments

Nell Rose profile image

Nell Rose 6 years ago from England

Hi, headless cockroaches? yuck! wow, being able to live after losing their heads! I never knew that! I remember the massive cockroach we saw when we went to Morocco, it was in a toilet! you can imagine, can't you? ha ha I have never used the toilets so quick in all my life! thanks for the info, it was fascinating, cheers nell


AliciaC profile image

AliciaC 6 years ago from British Columbia, Canada Author

Hi Nell. I love animals, but it’s hard to get fond of creatures like cockroaches that transmit diseases, even though they are just trying to survive! They’re interesting animals to study, though.


CMHypno profile image

CMHypno 6 years ago from Other Side of the Sun

Hi Alicia, fascinating hubs on cockroaches. You don't generally see too many roaches in the UK although there are plenty around (I once worked as a waitress in an old building in London where you had to stamp on the floor before you turned the light on as there would literally be a carpet of them that you could hear rustling as they ran for cover) but nothing like the pony-sized cockroaches you find under the sofa cushions or behind the loo in Australia!


AliciaC profile image

AliciaC 6 years ago from British Columbia, Canada Author

Wow! I've never had experiences like these with cockroaches. Thanks for the comment, CMHypno.


jantamaya profile image

jantamaya 5 years ago from UK

Thank you for this very informative hub. Finally I can get some information about those 'monsters'. As I was living in Poland and Germany I even didn't know how a cockroach might look alike. My first one I've ever seen was after a sunset in Kapiolani Park in Hawaii. I think they were cockroaches, they were huge, maybe 1.5 inch long. I was scared. Later I've seen many of them in a wooden house in the woods of Kentucky and some of them in a house in Costa Rica. Thankfully don't see any of them in Maryland! :-)


AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thank you for your comment, jantamaya. It seems like you've seen many cockroaches!


Extinct Soul profile image

Extinct Soul 5 years ago from 14°35'N 121°0'E

I hate roaches but this made me feel as if they were interesting..lol..I haven't read about roaches, this was really cool!

All those times I thought cockroaches don't have eyes..geez..thanks for sharing! ^_^


AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Hi, Extinct Soul. It's nice to meet you! Thank you for your kind comment.


christina 4 years ago

i have been trying to get rid of these gross things for almost a year. nothing is working because every other apartment has them. i get std tested once a year just to be safe and just found out i have hepatitis A. i never had it before i moved in here and i started getting sick a little while after i moved in. they are gross and nasty and i wish i never moved here and would never had if i knew it was infested with roaches.


AliciaC profile image

AliciaC 4 years ago from British Columbia, Canada Author

I'm sorry about what you are going through, Christina. I hope that you can find a place to live that is free of cockroaches.


ologsinquito profile image

ologsinquito 2 years ago from USA

Once, when I was in the Caribbean, I saw an enormous cockroach at least the size of a half dollar, and that's a conservative estimate. I'll take our American cockroaches any day.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Your experience sounds scary, ologsinquito! Thank you for sharing the story.


grand old lady profile image

grand old lady 2 years ago from Philippines

I must admit the cockroach brings out the sadist in me. I love to see them die slowly and painfully, and I use alcohol to do this. At the same time I feel the alcohol disinfects its green-bloody trail. Yes, cockroaches have green blood. Do you know, I actually hear a scream? Sounds like a low resonance amplifier but with definite emotion. It is music to my ears. I also learned that cockroaches love their families because when I return to my bathroom after an hour or so you can be sure another cockroach will be beside it, sometimes one of the same size, smaller or larger. Kapow! Alcohol death once again. I know there are better and less expensive ways to do this like cockroach spray, but these creatures are vengeful. I've sprayed cockroaches on the wall and they fly toward me so I'm moving back screaming and continuing to spray. With alcohol they don't fly, they are too disoriented. Cockroaches are the devil.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Hi, grand old lady. I can tell that you absolutely hate cockroaches! They can certainly be horrible pests. I hope I'm never in a situation where I have to fight them. Cockroaches generally have colorless blood, but they sometimes release a green liquid as their internal organs are damaged. They don't have vocal cords, but I've heard about the screaming sound that you've mentioned before. I hope I never hear it in real life! Good luck with your battle against roaches.


The brown kid 2 years ago

Hi, I'm just so terrified of these things to the point where I hesitate to kill them cause I don't want all their juices everywhere. I have to crush them(so they don't suffer) and then clean the WHOLE area around them. Just so their remains won't attract another. I just pray they don't crawl over me while I sleep


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Hi. I know what you mean! A cockroach encounter can be very unpleasant. Although I think cockroaches are interesting insects, I would hate to have one crawling over me while I slept. That would definitely give me a nightmare!


The brown kid 2 years ago

Yea your right. And the feed back is incredible. From you I mean. I wasn't expecting it to be so soon and responsive. And to respond to Grand old lady; they eat their dead. So you prob interrupted a feast. Don't get me wrong though, they'll eat other dead roaches too. Lol


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Hi again, and thank you. Cannibalistic cockroaches - what an image!

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    Linda Crampton (AliciaC)1,248 Followers
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    Linda Crampton is a teacher with an honours degree in biology. She loves to study nature and write about animals and plants.



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