Cockroach
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 Madagascan Hissing Cockroach, Gromphadorhina portentosa. This insect is 8 cm (3 in) long.
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Families
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Blaberidae Blattellidae Blattidae Cryptocercidae Polyphagidae Nocticolidae |
Cockroaches are insects of the order Blattodea (the name Blattaria is also seen). The names of the order are derived from Greek blatta, meaning "cockroach". There are roughly 3,500 species in 6 families. Cockroaches exist worldwide, with the exception of the polar regions and in elevations above 2,000 m (6,500 ft).
Among the most well-known species are the American cockroach, Periplaneta americana, which is about 3 cm long, and the German cockroach, Blattella germanica, about 1.5 cm long. Tropical cockroaches are often much bigger. When infesting buildings, cockroaches are considered pests.
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 termites and mantids as well as modern cockroaches. In fact, current evidence strongly suggests that termites have evolved directly from true cockroaches. The first fossils of "modern" cockroaches with short ovipositors appear in the early Cretaceous. Mantodea and Blattodea are included by some entomologists together in a single order, 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, making it an evolutionary link between cockroaches and the termites that evolved from them. 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 other words, in favorable conditions it can produce 300–400 offspring. A regular cockroach, however, can produce an extremely high number of eggs in her lifetime. She lays up to 100 eggs in each egg sac. She only needs to be impregnated once to be able to lay eggs for the rest of her life, allowing one single cockroach to lay over a million eggs in her lifetime.
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 massive.
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. Roaches are called the custodians of nature. They only live in houses where there are crumbs to eat or the garbage can is uncovered. They lay eggs inside the house's hollow walls.
The roach is also one of the hardiest insects on the planet, capable of living for a month without food and remaining alive headless for up to a week. It can also hold its breath for 45 minutes and has the ability to slow down its heart rate. Cockroaches also have a very high resistance to radiation. [1]
Select 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
- Blatta marimantaringisis, Large-headed stink cockroach
Madagascar Hissing Cockroach
The Madagascar hissing cockroach (Gromphadorhina portentosa) is a large flightless insect from the forests of Madagascar. It lives under the bark of trees or in leaf litter, feeding on plant matter including leaves and fallen fruit. It is an ovoviviparous organism. It is one of the largest cockroaches in the world and can reach 8 cm (3 inches).
Any predator that catches one of these cockroaches is in for a double shock. The legs of this insect are covered in needle-sharp spines and the cockroach can make a loud hissing sound. It does this by forcing air out of the breathing holes that run along the side of its body.
Although they live in the forest, they are attracted by house lights, and will sometimes creep through open windows. However, they are harmless and will soon leave when disturbed. The Madagascan Hissing Cockroach is often used in television programmes and films where a large scary-looking insect is required. They are frequently used in the television program " Fear Factor" where they are used to scare contestants or they have to be eaten. Because they are flightless, relatively slow-moving, and lack the offensive odor of many other roaches, they are sometimes kept as pets.
One Madagascan Hissing Cockroach has the privilege of being the driver of a Cockroach Controlled Mobile Robot. [2]
Behavior
New 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, water, and where other cockroaches are hiding. One of the major implications of this research is a new technique in cockroach pest control. Cockroaches could be potentially removed from a home by leaving a chemical trail that leads away from the home.
Habitat
Cockroaches adapt readily to a variety of environments, and prefer warm conditions such as found within buildings.
Pest control
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 faucets, should also be repaired. It is also helpful to seal off any entry points, such as holes around baseboards, pipes, doors, and windows. 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.
Popular Culture
In popular culture, cockroaches are often regarded as vile pests. For example, English translations of Franz Kafka's The Metamorphosis generally read that the protagonist found himself transformed into a giant cockroach (although the original German is ambiguous), which was anything but a positive change for him!
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 germophobic old man)
- Damnation Alley (A post-apocalyptic Las Vegas is infested 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.)
- Indiana Jones and the Temple of Doom (Cockroaches are among the many items served in a particularly memorable banquet scene.)
In the X-Files episode " War of The Coprophages" cockroaches are seen to group together to murder people. The show producers also digitally added a cockroach crawling "over" a quiet scene in the episode as an added scare. At first glance by the viewer it appeared as if a real cockroach was crawling over the television set.
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 "gynaecological disorders".