| Giant cockroach | |
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| Blaberus giganteus - Female | |
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| Blaberus giganteus - Female △ | |
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| Species: | B. giganteus
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| Binomial name | |
| Blaberus giganteus | |
Blaberus giganteus, the giant cockroach, is one of the world's largest cockroaches, potentially growing longer than the giant burrowing cockroach, though not as heavy. Their length can reach 90 mm (3.5 in). They are sometimes sold as exotic pets.
Habitat edit
Giant cockroaches are found in tropical areas of Central and South America, including Mexico, Guatemala, El Salvador, Panama, and several countries in the West Indies. They live in quiet, dark, humid places in rainforests, such as caves.
Sexual dimorphism edit
Male and female Blaberus giganteus are dramatically different in appearance. Females are longer and have large, translucent, light brown wings, while males are shorter but bulkier and lack wings. Males are also much more colorful than females, with bright red and orange patterns on their shells in addition to black.
Symbiotic relationship with bacteria edit
Like all cockroaches, Blaberus giganteus have a symbiotic relationship with the bacterium Blattabacterium cuenoti, which are found inside special cells called mycetocytes located within their fat bodies. These bacteria are passed on from the mother cockroach through the eggs to developing embryos. As they contain an enzyme responsible for breaking down uric acid, these bacteria seem to have a major role in the processing and elimination of waste nitrogen, which is stored around the locations of these cells. If removed or destroyed, their absence causes serious health problems (Wren, Johnson, & Cochran, 276.)
Behavior edit
Blaberus giganteus are nocturnal, operating on a cycle of active and resting periods. These cycles are unaffected by the temperature of their surroundings, but can be delayed by exposure to bright lights. They will not become active while kept under constant illumination. Unlike those of other nocturnal insects (such as field crickets), these rest and activity cycles cannot be "reset" by raising the temperature above a certain point or exposing them to several hours of constant darkness (Cloudsley-Thompson.)
Like other cockroaches in the family Blaberidae, female Blaberus giganteus carry their egg cases inside their bodies, rotating the structure of the ootheca and retracting it into a specialized organ known as a brood sac for protection. This can give the appearance of live birth, though Blaberus giganteus are not truly viviparous (Costa, 150-151.)
When picked up or otherwise pestered, they may secrete saliva onto their attacker as a defense mechanism. In some humans, this has been reported to cause skin irritation symptoms, including redness, itching, and the formation of welts, almost instantly upon contact (Kanerva, Kyllikki, Tupasela, Kaarsalo, & Estlander.)
Other names edit
The species Blaberus giganteus has also been referred to by the following names (Beccaloni & Eades.)
- Blatta livida Gronovius, 1764
- Sisapona marginalis Walker, 1868
- Blabera mexicana Saussure, 1862
- Blatta scutata Seba, 1765
- Blabera stollii Brunner von Wattenwyl, 1865
References edit
- Beccaloni, G., & Eades, D. C. Species Blaberus giganteus (Linnaeus, 1758): Blattodea species file. Retrieved from http://blattodea.speciesfile.org/Common/basic/Taxa.aspx?TaxonNameID=809
- Cloudsley-Thompson, J. L. (1960). Studies in diurnal rhythms -- x. synchronisation of the endogenous chronometer in blaberus giganteus (l.) (dictyoptera: Blattaria) and in gryllus campestris l. (orthoptera: gryllidae). Entomologia Experimentalis et Applicata, 3(2).
- Costa, J. (2006). The other insect societies. Cambridge, Mass.: Belknap Press of Harvard University Press.
- Kanerva, L., Kyllikki, T., Tupasela, O., Kaarsalo, K., & Estlander, T. (1995). Occupational allergic contact urticaria caused by cockroach (blaberus giganteus). Contact Dermatitis, 33(6), 445-456. doi: 10.1111/1600-0536.ep12052608
- Wren, H. N., Johnson, J. L., & Cochran, D. G. (1989). Evolutionary inferences from a comparison of cockroach nuclear DNA and DNA from their fat-body and egg endosymbionts. Evolution, 43(2), 276-281.
