Cockroach

Cockroaches are insects of the Order Blattodea. The name of the order is derived from the Latin word for "cockroach," blatta. There are roughly 3,500 species in six families. Cockroaches exist worldwide, with the exception of the polar regions. Cockroaches are also simply known as "roaches".

The English word cockroach is derived from the Spanish cucaracha through folk etymology.

Among the most well-known species are the American cockroach, Periplaneta americana, which is about 3 cm long, the German cockroach, Blattella germanica, about 1½ cm long, the Asian cockroach, Blattella asahinai, also about 1½ cm in length, and the Oriental cockroach, Blatta orientalis, about 2½ cm. Tropical cockroaches are often much bigger, and extinct cockroach relatives such as the Carboniferous Archimylacris and the Permian Apthoroblattina were several times as large as these. When infesting buildings, cockroaches are considered pests; out of the thousands of species, however, only a handful fall into this designation.

Evolutionary history and relationships

The earliest cockroach-like fossils are from the Carboniferous period between 354–295 million years ago. However, these fossils differ from modern cockroaches in having long ovipositors and are apparently the ancestors of mantids as well as modern cockroaches. Current evidence strongly suggests that termites have evolved, in turn, directly from true cockroaches. If this is the case, then Blattodea (excluding Isoptera) is not a monophyletic group. The first fossils of "modern" cockroaches with short ovipositors appear in the early Cretaceous. Mantodea, Isoptera, and Blattodea are usually combined by entomologists into a higher group called Dictyoptera.

Biology

Cockroaches are generally either scavengers or omnivores. The exception to this is the wood-eating Cryptocercus species found in China and the United States. Although they are incapable of digesting the cellulose themselves, they have a symbiotic relationship with a protozoan that digests the cellulose, allowing them to extract the nutrients. In this, they are similar to termites and current research suggests that the genus Cryptocercus is more closely related to termites than it is to other cockroaches. Cockroaches are most common in tropical and subtropical climates. Some species are in close association with human dwellings and widely found around garbage or in the kitchen.

Female cockroaches are sometimes seen carrying egg cases on the end of their abdomen; the egg case of the German cockroach holds about 30–40 long, thin eggs, packed like frankfurters in the case called an ootheca. The eggs hatch from the combined pressure of the hatchlings gulping air and are initially bright white nymphs that continue inflating themselves with air and harden and darken within about four hours. Their transient white stage while hatching and later while molting has led to many individuals claiming to have seen albino cockroaches.

A female German cockroach carries an egg capsule containing around 40 eggs. She drops the capsule prior to hatching. Development from eggs to adults takes 3-4 months. Cockroaches live up to a year. The female may produce up to eight egg cases in a lifetime; in favorable conditions, it can produce 300-400 offspring. Other species of cockroach, however, can produce an extremely high number of eggs in a lifetime. Laying up to 100 eggs in each egg sac, it only needs to be impregnated once to be able to lay eggs for the rest of its life, allowing one single cockroach to lay over a million eggs during its lifespan.

The world's largest cockroach is the Australian giant burrowing cockroach, which can grow to 9 cm in length and weigh more than 30 grams. Comparable in size is the giant cockroach Blaberus giganteus, which grows to a similar length but is not as heavy.

Cockroaches are mainly nocturnal and will run away when exposed to light. A peculiar exception is the Oriental cockroach, which is attracted to light, thus making it a far more annoying pest.

The cockroach is also one of the hardiest insects on the planet, capable of living for a month without food. It can also hold its breath for 45 minutes and has the ability to slow down its heart rate.

It is popularly suggested that cockroaches will "inherit the earth" if humanity destroys itself in a nuclear war. Cockroaches do indeed have a much higher radiation resistance than vertebrates, with the lethal dose perhaps 6 to 15 times that for humans. However, they are not exceptionally radiation-resistant compared to other insects, such as the fruit fly .^[1]

The cockroach's ability to withstand radiation better than human beings can be explained in terms of the cell cycle. Cells are more vulnerable to effects of radiation when they are dividing. A cockroach's cells divide only once when in its molting cycle, which at most happens weekly. The cells of the cockroach take roughly 48 hours to complete a molting cycle, which would give time enough for radiation to affect it but not all cockroaches would be molting at the same time. This would mean some would be unaffected by the initial radiation and thus survive, at least until the fallout arrived.^[2]

Selected species

• Periplaneta americana, American cockroach
• Eurycotis floridana, Florida woods cockroach
• Blatta orientalis, Oriental cockroach
• Blattella germanica, German cockroach
• Blattella asahinai, Asian cockroach
• Pycnoscelus surinamensis, Surinam cockroach
• Supella longipalpa, brown-banded cockroach
• Periplaneta australasiae, Australian cockroach
• Periplaneta fuliginosa, smokybrown cockroach
• Parcoblatta pennsylvanica, Pennsylvania woods cockroach
• Periplaneta brunnea, brown cockroach
• Blaberus discoidalis, discoid cockroach or false death's head
• Blaberus craniifer, true death's head cockroach
• Gromphadorhina portentosa, Madagascar hissing cockroach

Behaviour

Cockroaches have been shown to exhibit emergent behaviour.^[3]

Research being conducted at the University of Florida shows that cockroaches leave chemical trails in their feces. Other cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding. One of the major implications of this research is a new technique in cockroach pest control. Cockroaches could potentially be removed from a home by leaving a chemical trail that leads away from the home.

Research has shown that group-based decision making is responsible for more complex behavior such as resource allocation. A study where 50 cockroaches were placed in a dish with three shelters with a capacity for 40 insects in each, the insects arranged themselves in two shelters with 25 insects in each, leaving the third shelter empty. When the capacity of the shelters was increased to more than 50 insects per shelter, all of the cockroaches arranged themselves in one shelter. Researchers found a balance between cooperation and competition exists in group decision-making behavior found in cockroaches. The models used in this research can also explain the group dynamics of other insects and animals.^[3] The nerve poison induces muscular spasms which often result in the cockroach flipping on its back. Without muscular coordination, the cockroach cannot right itself and eventually dies in its upside-down position.

Cockroaches can survive on very little food; it has been discovered that cockroaches will eat the glue from the back of postage stamps when little else is available.

A person who is allergic to consuming shellfish is also likely to have an allergy to eating cockroaches.^[4]

Pest control

There are numerous parasites and predators of cockroaches, but few of them have proven to be highly effective for biological control. Wasps in the family Evaniidae are perhaps the most effective insect predators, as they attack the egg cases, and wasps in the family Ampulicidae are predators on adult and nymphal cockroaches (e.g., Ampulex compressa). The house centipede, however, is probably the most effective control agent of cockroaches, though most homeowners find the centipedes themselves objectionable. Preventative measures include keeping all food stored away in sealed containers, using garbage cans with a tight lid, frequent cleaning in the kitchen, and regular vacuuming. Any water leaks, such as dripping taps, should also be repaired. It is also helpful to seal off any entry points, such as holes around baseboards, in between kitchen cabinets, pipes, doors, and windows with some steel wool or copper mesh and some cement, putty or silicone caulk. Once a cockroach infestation occurs, chemical controls may help alleviate the problem. Bait stations, gels containing hydramethylnon, as well as boric acid powder, are toxic to cockroaches. Baits with egg killers are also quite effective at reducing the cockroach population. A simple homemade Vegas cockroach trap is reported to be successful. Additionally, pest control products containing deltamethrin are very effective.

Popular culture

In popular culture, cockroaches are often regarded as vile and extremely resilient pests, due to their shiny exoskeletons (making them look slimy, contrary to their fastidious habits), and their size, unusual for a scavenging insect.

Movies which feature cockroaches include:

• Joe's Apartment — The bugs are cheerful, swinging party-goers who help the titular human hero.
• Creepshow — Swarms of them terrorize a cantankerous and verminophobic old man.
• Damnation Alley — A post-apocalyptic Las Vegas is infected with a flesh-eating mutant variety.
• Men in Black — A giant cockroach-like alien's actions threaten to lead to the destruction of the Earth.
• Mimic — Diseased cockroaches are the target of the genetically-altered titular species.
• Team America: World Police — After his apparent death, a coachroach crawls out of Kim Jong-il's mouth and flies away in a rocket ship, in parody of Men in Black.
• Twilight of the Cockroaches — An anime film in which roaches live peacefully in a bachelor's apartment until he begins dating a woman across the street, who encourages genocide of the insects.

In Franz Kafka's existentialist story The Metamorphosis, the character Gregor Samsa awakes to find himself transformed into a giant insect, often mislabeled as a cockroach. Actually, the type of bug in which Gregor transforms is not specified, though it is referred to as "vermin" and the little physical description offered could match either a cockroach or beetle.

In the X-Files episode "War of the Coprophages", cockroaches are seen to group together to murder people. The character Dr. Berenbaum (based on the University of Illinois entomologist) suggests that it is actually swarms of flying cockroaches that are responsible for most UFO sightings (they generate an electro-static field which can be illuminated dependent on atmospheric conditions). In one of the scenes, a cockroach that escaped can be seen crawling over the camera, making it appear that the viewer's television has become infested. Though the shot was not planned, the producers decided to leave it in the episode.

In the television show ALF, Alf inadvertently releases a Melmacian cockroach in the house. When it is sprayed with insecticide, it grows bigger until it is large enough to eat him. He discovers that a bottle of perfume will kill the cockroach.

The famous Mexican folk song, La Cucaracha, means "The Cockroach" in Spanish, and refers to cockroaches in some of its lines.

In Revolt of the Cockroach People, an autobiographical novel by Oscar Zeta Acosta, cockroaches are used as a metaphor for oppressed and downtrodden minorities in US society in the 1960s and 70s, particularly Mexican-Americans. There are several references to the folk song La Cucaracha throughout the novel.

In 1987, Los Angeles rapper Bobby Jimmy released the song "Roaches" as a parody of Timex Social Club's hit song "Rumors". Its chorus line was Look at all these roaches / Around me everyday / Need somethin' strong / To make 'em go away.

The cult computer game Bad Mojo deals with a person turned into a cockroach, in clear reference to Kafka's Metamorphosis.

Archy is a cockroach in a series of columns by Don Marquis.

Megalon is a 50 meter tall cockroach that appears in several Japanese Godzilla films.

Along with rats, cockroaches are frequently seen infesting various locations in sam and max comics, and one storyline features a race of gigantic cockroaches living on the moon.

In the Discworld novel The Last Continent, Ponder Stibbons is horrified to learn that the cockroach is actually the most highly evolved and advanced creature in the world, and not mankind as he had assumed.

Tyler Knox published a noir comedy in 2006 called "Kockroach" (William Morrow) in which a cockroach wakes up one morning as a man and becomes a leading gangster in Times Square during the 1950s.

Believed in urban legend to be the only surviving creatures in the event of a nuclear war.

History

Some of the earliest writings with regards to cockroaches encourage their use as medicine. Pedanius Dioscorides (1st century), Kamal al-Din al-Damiri and Abu Hanifa ad-Dainuri (9th century) all offered medicines that either suggest grinding them up with oil or boiling. The list of ailments included earaches, open wounds and "gynecological disorders."^{[citation needed]}

Miscellaneous

• The largest by weight is a 50 g Macropanesthia rhinoceros.
• The smallest species is Attaphila fungicola, reaching only 4 mm.

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