Cockroach

Cockroaches
Periplaneta americana
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Subclass: Pterygota Infraclass: Neoptera Superorder: Dictyoptera Order: Blattodea
Families
Blaberidae Blattellidae Blattidae Cryptocercidae Polyphagidae Nocticolidae

Cockroach is the common name for any insect in the order (or suborder) Blattodea (= Blattaria) in the superorder (or order) Dictyoptera, characterized by an oval, flat-bodied shape, leathery wings, long antennae, long legs, and a flat extension (or thoracic shield) that extends dorsally to conceal the head. There are more than 3,500 species of cockroaches.

Cockroaches are also known as "roaches" or as "cucarachas" in Spanish (from cuca for caterpillar). The name comes from the Spanish, by way of the obsolete word cacarootch. The scientific name derives from the Latin word for "cockroach", blatta.

Overview

As arthropods, cockroaches have jointed appendages, an exoskeleton (hard, external covering made mostly of chitin), segmented body, ventral nervous system, open circulatory system, digestive system, and specialized sensory receptors.

As insects, they are characterized by three pairs of jointed legs; an abdomen that is divided into 11 segments and lacks any legs or wings; and a body separated into three parts (head, thorax, and abdomen), with one pair of sensory antennae on the head.

Cockroaches are classified as "true insects" (that is, species classified in the Class Insecta). True insects are distinguished from all other arthropods in part by having ectognathous, or exposed, mouthparts. This is the reason they are sometimes termed Ectognatha, which is synonymous with Insecta.

Cockroaches are classified in the superorder (or order in some classifications) Dictyoptera. The use of the term Dictyoptera has changed over the years, and while largely out of use for much of the last century, it is becoming more widely used. It is presently usually considered a superorder, with Isoptera (termites), Blattodea or Blattaria (cockroaches), and Mantodea (mantids) being its three orders. In some classifications, however, Dictyoptera is shifted to order status, and Blattodea or Blattaria to suborder status. Regardless, in all classifications, the three constituent groups are the same, just treated at different rank. Although all modern Dictyoptera have short ovipositors, the oldest fossils of Dictyoptera have long ovipositors, much like members of the Orthoptera.

Description

A bush cockroach

Cockroaches live in a wide range of environments around the world. Pest species of cockroaches adapt readily to a variety of environments, but prefer warm conditions such as found within buildings. Many tropical species prefer even warmer environments and do not fare well in the average household. Only about 20 species of cockroaches out of the 3,500 are suited to thrive in the typical home.^{[citation needed]}

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. Cockroaches are generally considered pests; however, only about 30 species (less than 1%) infest urban habitats.^{[citation needed]}

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, like all insects, breathe through a system of tubes called tracheae. The tracheae of insects are attached to the spiracles, excluding the head. Thus, all insects, including cockroaches, can breathe without a head. The valves open when the CO₂ level in the insect rises to a high level; then the CO₂ diffuses out of the tracheae to the outside and fresh O₂ diffuses in. The tracheal system brings the air directly to cells because they branch continually like a tree until their finest divisions tracheoles are associated with each cell, allowing gaseous oxygen to dissolve in the cytoplasm lying across the fine cuticle lining of the tracheole. CO₂ diffuses out of the cell into the tracheole.

Insects do not have lungs and thus do not actively breathe in the vertebrate lung manner. However, in some very large insects the diffusion process may not be sufficient to provide oxygen at the necessary rate and body musculature may contract rhythmically to forcibly move air out and in the spiracles and one can actually call this breathing.[1]

Female Blatella germanica with ootheca

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 to claim to have seen albino cockroaches.

Common household roaches A. German cockroach, B. American cockroach, C. Australian cockroach, D&E. Oriental cockroach (♀ & ♂)

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, but only needs to be impregnated once to be able to lay eggs for the rest of its life.

Cockroaches are mainly nocturnal and will run away when exposed to light. A peculiar exception is the Oriental cockroach, which is attracted to light.

Cockroaches are generally omnivores. An exception to this is the wood-eating genus Cryptocercus, with various species found in Russia, China, Korea 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.

Cockroaches are among the hardiest insects on the planet, some species capable of remaining active for a month without food, or being able to survive on limited resources like the glue from the back of postage stamps. Some can go without air for 45 minutes or slow down their heart rate.

Cockroaches can survive sterile surgical decapitation for a very long period, especially if recently fed, but of course become unable to feed and die within a few weeks.

Ootheca of Periplaneta americana; Florianópolis, SC, Brazil

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 .

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 in a juvenile roach. 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.

Behavior

Cockroaches have been shown to exhibit emergent behaviour.

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.

Another study tested the hypothesis that cockroaches use just two pieces of information to decide where to go under those conditions: how dark it is and how many of their friends are there. The study conducted by José Halloy and colleagues at the Free University of Brussels and other European institutions created a set of tiny robots that to the roaches appear to be other roaches and can thus alter the roaches perception of critical mass.

Additionally, researchers at Tohoku University engaged in a Classical Conditioning experiment with cockroaches and discovered that the insects were able to associate the scent of vanilla and peppermint with a sugar treat.

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 the ancestors of mantids as well as modern cockroaches. The first fossils of modern cockroaches with internal ovipositors appear in the early Cretaceous.

Mantodea, Isoptera, and Blattodea are usually combined by entomologists into a higher group called Dictyoptera. Current evidence strongly suggests that termites have evolved directly from true cockroaches. If this is the case, then Blattodea excluding Isoptera is not a monophyletic group and the Isoptera are actually a family (or epifamily) of cockroaches. [2].

Selected species

Oriental cockroach (Blatta orientalis). a, female; b, male; c, side view of female; d, young.

• 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

Cockroaches and humans

A 2005 US national study on factors that affect asthma in inner-city children shows that cockroach allergens appear to worsen asthma symptoms more than other known triggers. This study, funded by the US National Institute of Environmental Health Sciences (NIEHS) and the US National Institute of Allergy and Infectious Diseases (NIAID), is the first large-scale study to rank asthma triggers according to severity.

Additionally, a 2005 research study, sponsored by the National Pest Management Association (NPMA), shows a disparity in homeowner knowledge about this link. Only 10% of homeowners in the USA feel that cockroaches are a threat to their family's health.

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]}

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 Salt Lake City, Utah is infected with a four-inch long, flesh-eating mutant variety (played by the Madagascar Hissing Cockroach).
• Bug (1975 film) also starred Madagascar Hissing Cockroaches, this time able to produce fire from their abdomens, wreaking havoc.
• Men in Black — A giant cockroach-like alien's actions threaten to lead to the destruction of the Earth.
• Team America: World Police — After his apparent death, a cockroach crawls out of Kim Jong-il's mouth and flies away in a rocket ship, in parody of Men in Black.
• Mimic — Diseased cockroaches are the target of the genetically-altered titular species.
• 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 killing the insects.
• A Nightmare on Elm Street 4: The Dream Master, Debbie is working out when she falls asleep on the bench, giving Freddy full reign of turning her into a cockroach (her biggest fear), and being squished to death.
• An American Tail, the chief villain, Warren T. Rat, carries with him a cockroach named Digit who he forces to count his money and frequently abuses, even threatening to eat him at one point.
• Naked Lunch, the main character, William Lee's "case worker" appears to him in the form of large cockroach that speaks through a hole in its abdomen. Later, this cockroach appears again as a hybrid of a cockroach/typewriter that has a keypad on its face. The case worker reveals his name as "Clark Nova", which also happens to be the name of Lee's typewriter model.
• Godzilla vs Gigan, both King Ghidorah and Gigan are controlled remotely by Nebulans, an alien race of giant cockroaches that inherited a waste planet after the dominant species on it polluted it into oblivion.
• The 1983 film Scarface, Tony refers to Gasper Gomez and the Diaz Brothers, rival gang leaders to Frank Lopez, as cockroaches in one of the film's most famous lines: "I'll bury those cock-a-roaches."
• Starship Troopers — in one scene, a group of children show their support for the war effort against the huge alien insect creatures by squashing cockroaches in the school yard.

Television shows which have featured cockroaches include:

• 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 because they can 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.
• 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 short-lived kids television show Freaky Stories was hosted by a cockroach named Larry.
• Heroes, Mohinder Suresh (a genetics professor) describes cockroaches, and not humans, as the pinnacle of evolution. The series' main antagonist, Sylar, is also associated with cockroaches in a couple of scenes.
• They are referred to in the episode "Insect Inside" of The Powerpuff Girls.
• In the television show "King of the Hill", the character Dale Gribble has been shown as a breeder of cockroaches. He attempts to breed a colony of Madagascar hissing cockroaches to do his bidding, theorizing that they will believe he is their mother and obey if he is the first thing they see when they hatch.

Written works which feature cockroaches include:

• Franz Kafka's story The Metamorphosis, the character Gregor Samsa awakes to find himself transformed into a giant insect, often interpreted as a cockroach. Actually, the type of bug into 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. Conversely, 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.
• 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.
• Daniel Evan Weiss's novel The Roaches Have No King tells the story of a humanized colony of cockroaches, who swear revenge against their hosts for renovating the kitchen and thus preventing easy access to food supplies.
• In the Discworld novel The Last Continent by Terry Pratchett, 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.
• Along with rats, cockroaches are frequently seen infesting various locations in Steve Purcell's comic book series Sam & Max, and one storyline features a race of gigantic cockroaches living on the moon.
• Archy is a cockroach in an historic series of newspaper columns by Don Marquis.

Games which feature cockroaches include:

• The cult computer game Bad Mojo deals with a person turned into a cockroach, in clear reference to Kafka's Metamorphosis.
• Deadly Rooms of Death (DROD), cockroaches are considered as flesh-eating monsters, which infest dungeons of all kinds.
• The role playing game Werewolf: The Apocalypse feature a tribe of werewolf, the Glass Walkers who have the unusual totem Cockroach as their spiritual patron, the Glass Walkers find themselves semi-pariahs among their brethren for their love for the city (and, to a lesser extent, for their affinity for humanity and its technology).

Music which features cockroaches include:

• 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.
• Hardcore rapper Necro has a track called "Cockroaches" in which he raps about people's fear and/or dislike of cockroaches.
• The album Infest from Papa Roach features a large roach on the cover.
• The Shuffle Demons did a song in 1986, Get Out Of My House, Roach, on the album Streetniks
• Sleepytime Gorilla Museum's second studio album, Of Natural History features the song Cockroach, which describes cockroaches with disgust.
• The album Lonesome Crowded West published in 1997 by American indie rock band Modest Mouse contains a song titled Doin' the Cockroach.

A few have even taken "Cockroach" as a nickname:

• Boxing coach Freddie Roach was nicknamed La Cucaracha (The Cockroach) when he was still competing as a fighter.
• In Australian rugby league, the New South Wales State of Origin Team are informally known as the Cockroaches, due to the commonality of the cockroach as a household pest in that state. Their opponents, the Queensland State of Origin Team, are known as the Cane Toads, after that state's most common pest.

Pest control

File:Roach control.jpg

Cockroach control, with cockroach baits, boric acid, and hydramethylnon gel.

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 or fipronil, as well as boric acid powder, are toxic to cockroaches.^{[citation needed]} Baits with egg killers are also quite effective at reducing the cockroach population. Additionally, pest control products containing deltamethrin are very effective.^{[citation needed]}

Lowering the habitat temperature below freezing point may render most of the eggs infertile. This method may be practical in rural homes but it is highly unlikely to work in large cities.^{[citation needed]}

In Asia, car owners are known to use Pandan leaves as a natural cockroach repellent in their vehicles.

External links

• Blattodea Species File Online world catalogue of cockroaches. Retrieved December 1, 2007.
• Online book about cockroaches. Retrieved December 1, 2007.

• UC Davis on cockroaches. Retrieved December 1, 2007.
• The cockroach FAQ. Retrieved December 1, 2007.

• Harvard University fact sheet on American cockroaches. Retrieved December 1, 2007.

References

ISBN links support NWE through referral fees

• Cockroaches: Ecology, Behavior, and Natural History, by William J. bell, Louis M. Roth, and Christine A. Nalepa, ISBN 0-8018-8616-3, 2007
• Firefly Encyclopedia of Insects and Spiders, edited by Christopher O'Toole, ISBN 1-55297-612-2, 2002

• Insects: Their Biology and Cultural History, Bernhard Klausnitzer, ISBN 0-87663-666-0, 1987

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