What Are Cockroaches?

Of thousands of cockroach species, you're most likely to see these four. Learn what it means for your health if cockroaches invade your home and what you can do to get rid of them. (Credit: iStock/Getty Images)

Cockroaches are a type of insect. They come in thousands of species, but only a few of them are common household pests.

Cockroaches can be quite a headache in your household. Besides being unpleasant to see around, they also carry substances such as feces on their body. They can release these substances into the air, causing allergic reactions or asthma attacks. 

The debris from dead roaches, body parts, or poop also can trigger allergies or asthma. Roaches can also contaminate your food, utensils, and even the surfaces where you prepare your food. This may cause health hazards such as food poisoning and infections. But some of the ways people try to get rid of cockroaches may come with their own hazards.

You can identify a cockroach by its oval-shaped, flat, low-lying body. Cockroaches are fast-moving insects with six legs, wings, and long antennae.

There are a few cockroach types you may find in or around your home. Cockroaches develop from an egg (oothecae), then hatch into nymphs, and finally grow into adult cockroaches. Cockroach nymphs don’t have wings. They only develop wings in their adult stage.

A female cockroach mates and carries around the eggs or ootheca, which is pillow-shaped and has up to 48 eggs, depending on the species.

The common types of cockroaches you’re likely to find in your house include:

German cockroach (Blatella germanica)

American cockroach (Periplaneta americana)

Oriental cockroach (Blatta orientalis)

Brown-banded cockroach (Supella longipalpa)

Wood cockroach (for example, Parcoblatta pensylvanica)

There are many types of cockroaches. But the ones you're most likely to find come in just a few types. 

German cockroaches. The German cockroach is the most common in households. You will mostly find it in the kitchen hiding from the light in dark spaces. It’s a bronze-colored half-inch cockroach with two black stripes on the back of its head. Female cockroaches of this species are typically darker than the males. Although both have fully grown wings, they seldom fly and prefer to run. Only the older nymphs and adults have black stripes.

German cockroaches spend most of their lives hiding and only come out to feed and mate. They take about 2 months to grow from egg to adult. Their complete lifecycle usually takes about 100 days.

German cockroaches typically live in clusters near their food source and only come out when it’s dark. They're omnivores and eat just about anything. They also reproduce faster than other types of roaches. Because of this, the majority of German roaches in any population are in their nymph stages. You will mostly find the German cockroaches gathering under your stove, dishwasher, and refrigerator. They defecate and mark these places as clustering points. You can spot their feces as dark spots where they like gathering.

American cockroaches. The American cockroach is the largest on this list, growing to about 2 inches long. Despite their name, they aren't native to America. They were introduced to the U.S. from Africa and the Middle East and are now widespread. The American cockroach varies from red to almost brown in color, with a yellow band that outlines the area behind their heads and long, slender antennae. Both males and females have wings and can fly short distances.

They are less common in homes and mostly hang out in a sewer, basement, boiler room, or steam tunnel in a commercial building. It especially loves food processing establishments. They leave their eggs near such places, where they hatch after about 45 days. American cockroaches take about 15 months to grow from egg to adult.

Oriental cockroaches. The oriental cockroach, or the waterbug, is mostly found in garages, basements, and crawl spaces. This cockroach thrives in cool, moist places. So, you may find them outside hiding in mulch or leaves where they can live through the winter. This also makes them slow growers. You can identify them with their blackish color, shiny body, and small wings. Nymphs are usually brown but get darker as they develop into adults.

They’re not particularly active insects and move slower than most other types of cockroaches. They grow up to 1 ¼ inches long and have a flat body. Their size depends on their sex. Male oriental cockroaches are smaller than females. The males grow wings up to about half of their bodies, while females only get wing stubs. The oriental cockroach can’t fly. It takes them about 18 months to go from egg to adult. Their eggs take about 2 months to hatch.

Brown-banded cockroaches. The brown-banded cockroach lives in warm areas. You may find them in ceilings, electronics, light fixtures, motor housings, or sometimes outdoors. They are more colorful and a bit smaller than the German cockroach and may live even in non-food areas of the house.

The male brown-banded cockroach is golden orange in color and has a dark brown band. The females are darker and have lighter bands on the abdomen. The nymphs are darker with cream bands on their head, and a mostly golden orange abdomen. The males can fly with wings that cover their abdomen, while females are flightless due to their shorter wings. The brown-banded cockroaches are known to jump if they are disturbed.

Wood cockroaches. The name ‘woods cockroach’ is used to refer to a couple of roach species found outdoors. They eat rotting wood.

This doesn’t mean that they won’t enter your house when they get the chance. But you will more often find them in logs, trees, stumps, and woodpiles. They may get into your house during the spring to mate. This type of roach is also attracted to lighting. It only grows up to less than an inch long.

One type of wood cockroach is called the Pennsylvania wood cockroach. They're a common flying roach in that state. The females deposit egg capsules under fallen logs, rotting wood, loose barks of trees, or stumps. The egg stage lasts 34 days in the warm months of the year.

Cockroaches typically prefer living around the kitchen for easy access to food and water. Common places for cockroaches to hide out are:

Wall cracks

Behind or under furniture

Below the sink

Kitchen cupboards

Drains

Garden

Around water heaters

Signs of Cockroaches

There are several ways to know if you have cockroaches in your house.

Seeing live cockroaches. Cockroaches are most active at night, so you may see them scurrying across the floor or on walls and ceilings after dusk.

Finding cockroach droppings. They may look like ground pepper or small mouse droppings. They can be found in areas where cockroaches live and feed. You may also notice stains, caused by the cockroach’s fecal matter, that look like dark spots or smears in room corners or on the top of the doors.

Smelling a musty odor. Cockroaches give off a musty, unpleasant smell that can be noticeable if there's a large infestation.

Finding shed skins. As cockroaches grow, they shed their exoskeletons, leaving behind small, translucent bits of skin.

Seeing eggs or egg cases. Cockroaches typically lay their eggs in areas that are not easily accessible to humans, such as cracks, crevices, or the space behind appliances.

Cockroaches could make you sick, but they aren't especially dangerous and aren't going to attack or bite you. As cockroaches move around your house, they shed their body parts and excrete feces and saliva. When these substances get into the air they have an effect similar to that of dust mites in your house. They may trigger asthma or allergies when you inhale them.

Do cockroaches carry diseases?

Studies show that cockroaches are responsible for the spread of 33 types of bacteria, six varieties of parasitic worms, and seven types of pathogens. Cockroaches can spread germs and diseases including:

Diarrhea

Cholera

Typhoid fever

Leprosy

Dysentery

Plague

Poliomyelitis

Salmonella

E. coli

While most people consider these bugs a pest, they are important in the environment. For example, they play a role in:

Cockroach Allergy Symptoms

Cockroach allergens can cause chronic symptoms that last longer than other seasonal allergies. Otherwise, symptoms of a cockroach allergy will look similar to those of other allergies. Ask your doctor if you should get tested to find out if you're allergic to cockroaches.

You may have a cockroach allergy if you have some of the following symptoms:

There are various things you can do to get rid of roaches and cockroach germs or allergens. Consider:

To keep wood roaches or other roaches from coming inside your home:

Avoid bringing firewood inside unless you’re using it immediately. Otherwise, keep firewood outdoors and away from your house.

Keep a wide lawn to keep cockroaches from crawling in from the surrounding woods.

Use tight-fitting doors and windows with screening, and caulk cracks and crevices in the walls to further prevent entry.

Clean the rain gutters and other areas outside your home that are heavy with plant litter. 

Apply insecticides such as permethrin or bifenthrin outside your house. Spray it around the doors and windows to keep female cockroaches from crawling in. Also spray it near outdoor lights, around which male cockroaches fly.

If the infestation persists, contact professional pest control services to help you get rid of wood roaches.