Animal Diversity Web

Geographic Range

The American Cockroach, despite its name, is not native to North America but was most probably introduced via ships from Africa. It is currently worldwide in distribution.

(Smith & Whitman, 1992)

• Biogeographic Regions
• nearctic
  • introduced
• palearctic
  • introduced
  • native
• oriental
  • introduced
• ethiopian
  • native
• neotropical
  • introduced
• australian
  • introduced

• Other Geographic Terms
• cosmopolitan

Habitat

P. americana is found in many different habitats. Although they generally live in moist areas, they can survive in dry areas if they have access to water. They prefer warm temperatures around 84 degrees Fahrenheit and do not tolerate cold. They die at temperatures below 15 degrees Fahrenheit. These criteria are often met in large commercial buildings such as restaurants, bakeries, grocery stores, food processing plants, hospitals, etc., where cockroaches may infest food-storage and food-preparation areas, basements, and steam tunnels. They are also found, although not as commonly, in residences. During the summer months, they can be found outdoors in yards and alleys. In the United States this is the most common species found in city sewer systems. They can enter structures by being brought in, coming up from the sewer system via drains, or occasional mass migration from other structures, dumps, etc., during warm weather.

(Cochran, 1980; Smith & Whitman, 1992)

• Terrestrial Biomes
• savanna or grassland
• forest
• rainforest
• scrub forest

Physical Description

Periplaneta americana adults are about 1 3/8 to 2 1/8 inches (34-53 mm) long. Their color is a reddish brown except for a submarginal pale brown to yellowish band around the edge of their pronotal shield (Pronotal shield - an expanded version of the top surface plate of the front segment of the thorax). Both sexes are fully winged. The wings of males extend beyond the tip of the abdomen, while females' do not. They are poor to moderately good fliers.

Early instars of P. americana nymphs are uniformly grayish brown dorsally, paler ventrally, and shiny. The cerci (cercus [pl. cerci]- One of a pair of dorsal appendages at the posterior end of the abdomen) are slender, and distinctly tapered from the base with length about 5 times the width. Later instars are reddish brown with lateral and posterior margins of the thorax and lateral areas (sides) of abdominal segments somewhat darker. The cerci are about the same as in the early instars. The widest segments are 2.5 times as wide as long. The antennae are uniformly brown.

The cockroach's walking pattern can be described as follows:

"The cyclic movement of a walking leg consists of two parts, the power stroke (also stance phase or support phase) and the return stroke (also swing phase or recovery phase). During the power stroke, the leg is on the ground where it can support and propel the body. In a forward-walking animal, this corresponds to a retraction movement of the leg. During the return stroke, the leg is lifted off the ground and swung to the starting position for the next power stroke."

(Cruse 1990; Cochran 1980; Smith & Whitman 1992; Bio-Serv 1998)

• Other Physical Features
• ectothermic
• bilateral symmetry

Reproduction

Female P. americana produce many different sex pheromones to attract a suitable mate. Examples of these attractive chemicals include periplanone-B, periplanone-A, germacradien-9-one, cresol, phenol, undecen, hexenal, cyclohexanedial, hexanoic acid, dodecalactone, pentanone, and octanone. Sperm transfer occurs through the use of a spermatophore, which is sometimes eaten by the female because of its protein-rich nature. (Spermatophore- Capsule or packet enclosing sperm, produced by males of several invertebrate groups and a few vertebrates). Once fertilization has occurred, a female forms oothecae, or egg sacs. Parthenogenesis or egg production without fertilization does occur, but eggs either fail to hatch, or produce only a few nymphs. The ootheca is a dark reddish to blackish brown; about 3/8" (8 mm) long, with length about1.5 times the width. The female deposits her ootheca within a few hours or up to 4 days after it is formed. It is dropped or glued with an oral secretion to a suitable surface, usually in a crack or crevice of high relative humidity near a food source.

On average, females produce 9-10 (range 6-14; maximum 90) oothecae, each containing 14-16 eggs. Developmental time (egg to adult) is greatly influenced by temperature, varying from 168-786+ days but averaging about 600 days under ordinary room conditions. During this time, they molt 10-13 times. Adult females live about 440 days (range 102-588; maximum 913) at ordinary room conditions(e.g. 70°F/20°C), but at 84°F/29°C, adult females live about 225 days (range 90-706), whereas adult males live about 200 days (range 90-362) at 84°F/29°C.

The development of P. americana is hemimetabolous, meaning there is no major metamophosis. The nymphs look very much like small adults.

Nymphs are given no parental care; hatchling roaches are left to fend for themselves. The nymph grows by molting and it goes through about 13 molts before it reaches the adult form. The next to last nymphal stage has wing pads, but only adult cockroaches have wings.

(Bell, 1981; Smith & Whitman, 1992)

Behavior

Cockroaches spend 75% of their time squeezed into narrow cracks and crevices for safety. The most preferred harborages are those of the proper size that are located near food and water sources, and which are warm and have a high relative humidity.

(Smith & Whitman, 1992)

Food Habits

Roaches themselves will eat anything, including one another. There is very little organic material that a cockroach won't eat. The list includes bark, leaves, paper, wool clothes, sugar, cheese, bread, oil, lemons, ink, soap, flesh, fish, leather, other roaches (dead or alive), or their own cast-off skins and egg-capsules. Some of these items, such as cellulose, can not be digested by normal means. However, like cows and other grazing animals, cockroaches have a symbiotic relationship with a bacteria that allows them to digest such substances. Although they feed on many kinds of food, they show a particular fondness for fermenting food.

(Helfer, 1972; Boraiko, 1981)

Economic Importance for Humans: Negative

This species is harmful to humans, and its impact on human health and economies is substantial. The greatest potential harm is an agent for disease transmission. American cockroaches can transmit a variety of bacterial diseases by feeding on contaminated material, and then contacting people's food. Cockroaches are also the fourth most common allergen. 50-60% of all atopic and asthmatic people show intense reactions to cockroach extract. Sensitivity to cockroach allergens may be as high as 79% in asthmatic children in severely infested homes. The species also has a psychological impact on humans, causing anxiety and stress due to embarrassment and physical invasion (Bio-Serv 1998; Cochran 1980).

Conservation Status

This species is considered a pest, and there are no efforts being made to conserve it.

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Other Comments

As far as being a food source, cockroaches have a number of natural enemies. Spiders sometimes hunt them but are often too slow to catch the quick cockroach in a natural environment. Frogs, toads, and salamanders are more effective predators, and in Bermuda lizards are kept in the house to devour roaches. Finally, human beings from Australia to China to Japan have been known to eat roaches for nourishment or for medicinal value.

There is a picture of the American Cockroach at the following URL:

There is a 5-step process for the control of roaches.

1. Prevention. This consists of inspecting all incoming items for cockroaches and oothecae, and making sure that the building is in good physical condition to reduce entry.
2. Good sanitation. Such practices reduce the amount of available harborage, food, and water.
3. Inspection. A thorough inspection using a flushing agent and flashlight is the key to successful control because it determines where the infestations/populations are and therefore, where treatment is required.
4. Initial insecticide application. This utilizes residual baits, insect growth regulators (IGR's), liquids, aerosols, lacquers, and/or microencapsulated pesticides usually placed in cracks and crevices but occasionally on surfaces or in voids, and the dusting of appropriate voids.
5. Follow-up or maintenance service. Such service consists primarily of inspecting with a flashlight and flushing agent and/or the use of monitoring traps to find missed or newly introduced cockroaches, and treating any active infestation found.

(Bio-Serv 1998; Cochran 1980)

Contributors

Brad Stetson (author), University of Michigan-Ann Arbor.

References

Smith, Eric H. and Whitman, Richard C. 1992, National Pest Control Association Field Guide To Structural Pests. National Pest Control Association

Bio-Serv Corporation (Rose Exterminator Company / Fisher Pest Control) Technical Meetings, March 17-24, 1998

Cochran, D. G., J. M. Grayson, and A. B. Gurney. 1980. V. Cockroaches: Biology and control.

Bell, W. J., and K. G. Adiyodi. 1981. Reproduction. In: "The American Cockroach", W. J. Bell, and Adiyodi, K. G., Eds., Chapman & Hall; NY

Cruse, H.. 1990 What mechanisms coordinate leg movement in walking arthropods? Trends in Neuroscience, pgs: 13, 15-21. NY

Helfer, Jacques. 1972. How to Know the Grasshoppers, Cockroaches, and Their Allies, 2nd ed. William C. Brown Company: Dubuque.

Boraiko, Allen A. 1981. "The Indominable Cockroach". National Geographic 159 No. 1