Cockroaches
Cockroaches are among the oldest and most primitive insects, with a lineage dating back to the Carboniferous period, approximately 350 to 320 million years ago. They are characterized by their flattened, oval bodies, long antennae, and shiny brown or black exoskeletons, which protect their bodies made of chitin. These nocturnal insects typically inhabit warm, dark, and damp environments, emerging at night to feed on various organic materials, including plants, decaying matter, and even manufactured products like cardboard and paper. Cockroaches undergo three life stages: egg, nymph, and adult, with females capable of producing a significant number of offspring in a short time.
Several species of cockroaches exist, including the common German cockroach, known for its rapid reproduction, and the American cockroach, which can fly and prefers indoor environments. Cockroaches are resilient creatures, able to survive for extended periods without food or water, which can pose challenges in food storage and hygiene. Effective control measures include sealing entry points, inspecting items brought into the home, and maintaining cleanliness in food storage and waste disposal. Understanding their behavior and habitat can help mitigate potential infestations while respecting their ecological role.
Cockroaches
Cockroach Facts
Classification:
Kingdom: Animalia
Subkingdom:Bilateria
Phylum:Arthropoda
Subphylum:Hexapoda
Class: Insecta
Subclass: Pterygota
Order: Blattodea
Superfamilies: Blaberoidea, Blattoidea, Corydioidea
Families:Blaberidae (giant cockroaches), Blattellidae (wood cockroaches), Blattidae (American cockroaches, oriental cockroaches), Cryptocercidae (brown hooded cockroaches), Polyphagidae (sand cockroaches),
Species: Over 4,500 species, about forty considered household pests
Geographical location: Every continent except Antarctica
Habitat: Land (forests, deserts, and grasslands)
Gestational period: Varies greatly, but typically forty to sixty days
Life span: Five months to one and a half years, depending on the species
Special anatomy: Oval body, brown or black; two pairs of wings in males; females usually wingless; eggs carried in an egg case (ootheca)
Cockroaches are one of the oldest and most primitive of insects. They flourished during the Carboniferous period of the earth’s history, 350 to 320 million years ago, which has been nicknamed “The Age of Cockroaches” by paleontologists. The fossil evidence uncovered indicates that during this time, cockroaches made up about 40 percent of the world’s insect population. Cockroaches from 340 million years ago looked much like roaches living today.
Cockroaches have a flattened, oval body, long, slender antennae, and a shiny black or brown exoskeleton. Most species also have wings that are held flat over the back. The exoskeleton, or shell, is made of chitin, which is about as thick as a human hair. The chitin covers the roach’s entire body, even its eyes. Cockroaches range from about 0.5 to 2 inches in length, with the largest being found in the tropics. They have grasshopper-like mouth parts for chewing and feed on plants or animal matter, including dead insects and bedbugs or even cardboard, paper, books, glue, and other manufactured products. They are nocturnal insects and are rarely active or visible during the day. They live and hide in warm, damp, dark places, coming out at night to hunt for food.
The cockroach has three life stages: egg, nymph, and adult. Cockroach eggs are deposited in groups in a leathery case or capsule, the ootheca. There may be from thirty to forty-eight eggs in the capsules of some species, while others have only ten to twenty-eight. The newly hatched nymphs have no wings and shed their skins (molt) several times before becoming winged adults. Indoor roaches generally have several generations of young per year, but outdoor species may require a full year to develop from egg to adult.
Cockroach Classification
The German cockroach, Blatella germanica, also called the “water bug” in some places, is found worldwide. It is commonly carried home in paper grocery bags and boxes (where it hides because it loves the taste of glue) and also likes to live around water pipes. Though it has only a 150-day life span, one adult female can produce as many as eight egg capsules, each filled with up to forty eggs. Thus, a female can produce more than 3,200 young in her lifetime. According to a bulletin from the US Food and Drug Administration, one female could be the source of over ten million females in a single year and over ten billion females in one and a half years, assuming that all the babies survived and reproduced and food supplies were adequate.
The German roach is relatively small in size, about one-half inch long, compared to some of its Asian relatives. The Asiatic (or oriental) cockroach, Blatta orientalis, can be up to two inches long and is considered one of the dirtiest household pests. It is oval in shape, with a shiny black exoskeleton. Males have short wings and can fly, unlike females, who have only vestigial wings. This species is found worldwide, having been carried almost everywhere by ships, trucks, railroad cars, and airplanes.
The American cockroach, Periplaneta americana, is found in most warm climates worldwide. It prefers to live indoors and is found in basements and furnace rooms. It has a life span of about one and a half years and lays about sixteen eggs every forty-five days. It originally came from Central and South American rainforests. The American roach has a set of wings that enable it to fly long distances.
The American and German species are cannibals. Young nymphs eat their own kind if there is not enough food available. Mothers frequently eat their own egg capsules if food shortages develop. However, roaches can survive for over a month without water or food. This feature has consequences for the food industry—for instance, roaches accidentally sealed in shipping crates can survive fairly comfortably even if shipped long distances with extremely limited resources.
Cockroaches are found in the desert as well as the forest. Southern California sand roaches, Arenivaga investigata, burrow under the sand during the hottest part of the day, coming out to feed only at night. They can absorb water merely by sticking out their tongues. The brown-hooded cockroach, Cryptocercus punctulatus, lives in decaying logs in the forest along the Atlantic coast. Only three other species of this genus survive, one in China, one in Russia, and one in the western United States because the forest habitat in which it thrives is disappearing. The Pennsylvania wood cockroach, Parcoblatta pennsylvanica, on the other hand, is found in abundance under logs and stones in northern forests. This species eats wood, which it digests with the help of bacteria living in its stomach, and is not considered a household pest.
Cockroach Control
Closing spaces and cracks around pipes, door frames, and baseboards can prevent cockroach infestations. Paper bags and cardboard boxes should be inspected for roaches when they are brought into the home. Store food in containers with tight-fitting lids. Pet food should be served by placing the bowl in a second, shallow bowl filled with soapy water. Roaches cannot swim across this barrier. Leaking water attracts roaches, so plumbing leaks should be fixed quickly. Sink and bathtub drains without stoppers are also inviting homes for roaches. Garbage cans should have lids and be emptied frequently. Cool temperatures can also kill roaches; few survive temperatures below freezing.
Principal Terms
Nocturnal: active at night
Vestigial: an organ that is no longer biologically useful
Bibliography
“Blattodea.” ITIS, Integrated Taxonomic Information System, 8 Nov. 2017, www.itis.gov/servlet/SingleRpt/SingleRpt?search‗topic=TSN&search‗value=174371#null. Accessed 31 Jan. 2018.
“Cockroach History and Some Interesting Facts.” Animalia Life, 2014, animalia-life.com/cockroach.html. Accessed 1 July 2023.
Gordon, David G. The Compleat Cockroach: A Comprehensive Guide to the Most Despised (and Least Understood) Creature on Earth. Berkeley: Ten Speed Press, 1996.
Guthrie, D. M., and A. R. Tindall. Biology of the Cockroach. New York: St. Martin’s Press, 1968.
Nuwer, Rachel. “How Many Species of Cockroaches Plague Humanity?” Smithsonian Magazine, 11 Dec. 2013, www.smithsonianmag.com/smart-news/how-many-species-of-cockroaches-plague-humanity-180948133. Accessed 1 July 2023.
Rust, Michael K., John M. Owens, and Donald A. Reierson, eds. Understanding and Controlling the German Cockroach. New York: Oxford University Press, 1995.