What makes our homes such inviting places for cockroaches? How do they survive? What makes them so adaptable? How can we prevent a cockroach invasion, and if we have been invaded, how can we get rid of them?

Cockroaches
How do they get into our houses and how can we get them out?
David goes to new depths to explore the life of a cockroach.
Segment length: 7:36

Insights

Cockroaches. We humans consider them the "rats of the insect world," yet cockroaches could be considered one of the most successful creatures on earth. Entomologists have found fossilized cockroaches that are more than 300 million years old. Amazingly enough, these fossilized cockroaches look very similar to the ones scurrying around in our yards and homes today.

There are over 4,000 species of cockroaches. As one of nature's recyclers, they are often found eating natural forest debris. A few find their way into our kitchens, basements, and bathrooms, coming up through the drains, sneaking in through cracks, or carried in on grocery bags. These cockroaches are usually looking for warm, moist, dark places to call home.

Cockroaches, by design, are survivors. They are nocturnal, making them hard to spot. If they are discovered, their flat bodies make it easy for them to escape into small crevices. Their antennae and cerci help them detect changes in vibrations and air pressure, making it difficult to even step on them. Cockroaches are omnivorous. They eat anything from dog food to plaster. Internal bacteria help cockroaches digest these unusual meals. If necessary, cockroaches can live for three months without food and one month without water.

Although cockroaches preen regularly, they are still suspected of transmitting diseases such as salmonella, dysentery, and typhus. They are also suspected of causing allergic reactions in half of the 17 million people afflicted with asthma.

Have cockroaches appeared in your home? Implement an Integrated Pest Management (IPM) program. First, start by making the site less attractive to cockroaches by storing food in tight containers and maintaining high sanitary standards. Then, if you must use pesticides, read the warning labels carefully. Traps and boric acid can be used instead of highly-toxic sprays. Although an IPM is a safer approach for the environment, following it probably won't enable you to get rid of cockroaches completely. Remember, cockroaches have been around for 300 million years. They are sure to be around for a long time to come.

Connections

1. Most cockroaches originated in Africa. Now they are found in all parts of the world. How might this spread of cockroaches have occurred?
2. You have just found cockroaches in your home. What will you do?

Vocabulary

antennae a pair of sensory feelers on the head of an insect
bacteria microscopic organisms that, in this case, aid in a cockroach's digestion
boric acid a medical antiseptic; a powder that acts as an insecticide for cockroaches
cerci small nerve endings on the back of a cockroach that can detect changes in air pressure and movement
entomologists scientists who study insects
nocturnal active at night
omnivorous eating both animals and plants; in the case of cockroaches, eating almost anything
palpi sensitive appendages attached to the oral part of a cockroach enabling it to pre-taste food

Resources

Insects. (1986) Washington, DC: National Geographic Society. Videotape.

Souza, D.M. (1991) Insects around the house. Minneapolis, MN: Carolrhoda Books.

Wenner, A.M., and H.D. Klein. (1991) Tiny-game hunting: Environmentally healthy ways to trap and kill the pests in your house and garden. New York: Bantam.

Additional sources of information:

Carolina Biological Supply Co.
2700 York Road
Burlington, NC 27215
(800) 334-5551

Connecticut Valley Biological
82 Valley Road
P.O. Box 326
South Hampton, MA 01073
(800) 628-7748

Community resources:

Pest exterminators
University entomology extension services

Main Activity

Caught One!
Design a cockroach trap. See if you can catch one.

Are cockroaches your invisible neighbors? Make a guess as to where you might find them. Design your own cockroach trap, or team up with your classmates. Then set out on an expedition to trap a cockroach.

Materials

  1. Coat the outside of your container with masking tape, black paint, or construction paper to make the inside of your container dark and inviting to a cockroach.
  2. Smear a wide band of petroleum jelly around the inside of the container just below the neck.
  3. Add bits of food to the container for cockroach bait.
  4. Where in your school, home, or community might cockroaches be hiding? Select a site, get permission, then go and set up your trap. Place the trap on its side. Create a miniature ramp using the cardboard strip or tongue depressor, extending the ramp from the floor to the container.
  5. If you catch a few cockroaches, quickly screw the lid on tightly. You don't want any cockroaches to escape. Notify the building authorities of your discovery.

Questions

1. What plan would you suggest to help get rid of the cockroaches at your specific site? What experiments can you devise to see how well your plan works?

2. Compare your cockroaches with those caught by your classmates. Are they the same types of cockroaches or are they different? Try to identify them.


What repels a cockroach? Experiment by putting a piece of bread in one end of a box and adding a cockroach. How long does it take for the cockroach to start eating the bread? Then, place a piece of peeled garlic into the box. Observe. Is the cockroach attracted to the garlic or repelled by it? Try bay leaves or cucumbers. Does your cockroach say "No thanks!" to these? Experiment with other foods.


Get out the calculators. A female German cockroach reproduces four to eight times in its life cycle, laying seven to eight egg cases, each case containing 35 to 40 eggs. About how many offspring might one female German cockroach have? Divide students into groups to solve the problem. Give each group a package of kidney beans to predict how many cockroaches their female would produce. Put all the beans together to see the effects of cockroach reproduction.


Find out how smart a cockroach can be. Design a cockroach maze. Start with a baking pan half-filled with water. Build a maze using several 6-oz. cans and strips of cardboard. Arrange the cans in the pan and place the cardboard strips on top of the cans to create two pathways. One pathway leads to the cockroach's home, the other leads to a dead-end. Put your cockroach at the start of the maze and observe.


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