| Blaberus giganteus | |
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Blattodea |
| Family: | Blaberidae |
| Genus: | Blaberus |
| Species: | B. giganteus |
| Binomial name | |
| Blaberus giganteus | |
| Synonyms | |
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Blaberus giganteus, the Central American giant cave cockroach or Brazilian cockroach, is a cockroach belonging to the family Blaberidae. One of the world's largest cockroaches, it is native to the warm parts of the Neotropical realm.
Blaberus giganteus is considered one of the largest cockroaches in the world, with males reaching lengths of up to 7.5 cm (3.0 in) and females 10 cm (3.9 in), [2] although others list 9 cm (3.5 in) as the maximum length. [3] These cockroaches are lightly built with flattened bodies, allowing them to hide in cracks from predators. Their bodies are brown with black markings. [4] The wingspan of these insects is usually around 15 cm (6 in). [3] Both males and females bear paired appendages (cerci) on the last abdominal segment, but only the males have a pair of tiny hair-like appendages called styli. Adults bear two pairs of wings folding back over the abdomen. [4] The heavier females are less likely to fly. [4]
This species is endemic to the Neotropics and can be found in caves and rainforests in Mexico, Guatemala, Panama, Colombia, Ecuador, Venezuela, Costa Rica, Brazil, Trinidad and Tobago, Cuba, Hispaniola (Dominican Republic), Guyana, Suriname, and French Guiana. [1] [5] Habitat preferences include areas of high moisture and little light, such as caves, tree hollows, and cracks in rocks. [5]
As typical for all roaches, individuals undergo hemimetabolous metamorphosis, which means the change from juvenile to adult is gradual. [6] The three distinct stages in their lifecycle are egg, nymph, and adult. Only adults are able to reproduce and have wings. [7] Prolonged nymphal stages, along with additional molts, can sometimes occur in B. giganteus for a number of reasons. One hypothesis is that the absence of the jostling and mutual stimulation which are found often in colony life could slow the developmental process. [8] In other instances, lower temperatures and reduced humidity can lead to delayed maturation and an increase in the number of molts. [8] This is a response by the insect to unfavourable habitat conditions and can also be seen as a predatory response. Their lifespans can last up to 20 months depending on habitat conditions and diet. [9]
Blaberus giganteus is a nocturnal omnivore and a scavenger, but the majority of its diet is decaying plant material. [2] Other food choices include bat guano, fruit, seeds, and carrion. [2] It is often associated with bats roosts, both in caves and hollow dung. They also prefer sweets, meats, and starches as their daily meal.
Two chemical signals play important roles in the sexual behaviour of B. giganteus. [10] The sex pheromone is released by the female and used in attracting mates that are long distances away. [10] The male produces an aphrodisiac sex hormone from his tergal glands that encourages female mounting. [10] Females choose the males with which they will mate, so this sexual selection becomes a major pressure and driving force behind natural selection. [7] Carbohydrate intake has been found to be related to male sex pheromone expression, dominance status, and attractiveness more so than protein. [7] Males have been shown to have a preference for a high-carbohydrate diet versus one focused on protein. [7] This would suggest they are actively increasing their carbohydrate consumption to maximize their reproductive fitness and attractiveness to potential female mates. [7] After mating, the female B. giganteus is pregnant for life and stores the fertilized eggs in her ootheca, where they are incubated for roughly 60 days. [10] When the eggs are about to hatch, the female expels the ootheca so the nymphs can break free and feed on their first meal, which consists of the ootheca. [10] After eating their fill, the young nymphs burrow into soil or somewhere dark and remain there until they have molted numerous times and reached maturity. [10]
When exposed to infection or invasion of various microorganisms, insects have two general responses of their immune systems. In B. giganteus, such an invasion elicits a humoral response, where specific proteins are produced or activated by the existence of a pathogen. [9] The fat body, which is usually associated with storing and releasing energy depending on demands, induces several novel proteins when confronted with fungal cell walls. [9] The giant cockroach exhibits adaptive humoral responses, [9] which means their immune response has a specific memory similar to what can be found in mammalian immune systems. [9] This is beneficial for long-lived individuals, as they have increased chances of encountering the same infection numerous times. [9] The biological significance of these proteins is yet to be determined, but they are known to play a role in defense against fungal infections. [9]
As for the majority of cockroaches, the Central American giant cave cockroach has a relationship with a genus of obligate flavobacterial endosymbiont called Blattabacterium . [2] They engage in a host-microbe relationship. [2] The microbe's job is to take nitrogenous waste such as urea and ammonia and process it into amino acids that can be used by the cockroach in the form of amino acids. [2] This is very beneficial to the cockroach because overall its diet is plant-based and considered very nitrogen-poor. [2] Though carbohydrate consumption is beneficial in mating, it does not play an active role in male-to-male competition. [7]
Cockroaches always have three legs in synchronous contact with the ground during movement. [11] The three legs are classified as the leading leg, middle leg, and trailing leg and the leading and trailing leg from one side with the middle leg of the other side forms a tripod. [11] The leading leg pulls the body, while the trailing leg pushes the middle leg forward. [11] The middle leg is important because it acts as a pivot and creates the characteristic zigzag locomotion. [11] The process is repeated with the next tripod, and to move forward, the tripods alternate. [11] The ability of cockroaches to have ground reaction force distributed equally to these three legs is explained by joint torque minimization, [11] which has been shown to help limit mechanical, energetic, and metabolic demands, and can also decrease the axial load on a single leg. [11] Cockroaches can easily walk up a 45° slope on a smooth surface with little to no difficulty. [11] However, aged cockroaches or cockroaches with damaged tarsi can overcome such slopes only with difficulty.
The rate of oxygen consumption in some animals and in insects is proportionate to body weight. [12] Oxygen consumption increases with activity and is subject to rhythmical cycles of activity exhibited in cockroaches. [12] Because cockroaches do not have lungs to breathe, they take in air through small holes on the sides of their bodies known as spiracles. [12] Attached to these spiracles are tubes called tracheae that branch throughout the body of the cockroach until they associate with each cell. [12] Oxygen diffuses across the thin cuticle and carbon dioxide diffuses out, which allows cockroaches to deliver oxygen to cells directly without relying on blood as do humans. [12] Differences in oxygen consumption occur between sexes of the same organism. Oxygen consumption in the mixed red and white muscles of mature male B. giganteus was higher when compared to mature females. [12] This is likely due to sex-related differences of sex hormones causing increased accumulation of oxidized substrates or increased concentration of enzymes in muscles in males. [12] Males have been shown to have higher levels of glycogen and mitochondria in muscle cells. [12] Because B. giganteus is so large, it is assumed to have a higher metabolic rate versus other cockroaches, such as Periplaneta americana , but in comparison, it is quite sluggish. [12] Rates of oxygen consumption are significantly higher in P. americana when compared to B. giganteus, likely due to higher daily rhythmic activity. [12]
Hemolymph is the fluid used in some arthropod circulatory systems, including insects, to fill the interior hemocoel. [13] Hemolymph is composed of water, inorganic salts, and organic compounds. [13] Some of the organic compounds are free amino acids, and the contents vary by species in terms of which amino acids are present and their overall concentrations. [13] The amino acids present in B. giganteus are alanine, arginine, cysteine, glutamic acid, glycine, histidine, leucine, proline, threonine, tyrosine, and valine. [13] The amino acids present in greatest proportions were glutamic acid, alanine, glycine, and histidine. [13] The overall concentration of amino acids is roughly 265 mg/100 ml of hemolymph. [13] The presence of alanine, cysteine, glutamic acid, leucine, proline, tyrosine, and valine is shared among different species of cockroaches, such as Blattella germanica and P. americana. [13] The presence of arginine, however, is species-specific to B. giganteus. [13]
Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph cells called hemocytes are suspended. In addition to hemocytes, the plasma also contains many chemicals. It is the major tissue type of the open circulatory system characteristic of arthropods. In addition, some non-arthropods such as mollusks possess a hemolymphatic circulatory system.
Giant cockroaches, or blaberids, are the second-largest cockroach family by number of species.
Reproductive success is an individual's production of offspring per breeding event or lifetime. This is not limited by the number of offspring produced by one individual, but also the reproductive success of these offspring themselves.
The Florida woods cockroach or palmetto bug is a large cockroach species which typically grows to a length of 30–40 mm (1.2–1.6 in). When alarmed, adults can eject an extremely foul-smelling directional spray up to 1 m, which inspired several of its other common names: Florida skunk roach, Florida stinkroach, skunk cockroach, skunk roach, stinking cockroach, and stinkroach. Two other naming variations include Florida cockroach and Florida woods roach.
The German cockroach, colloquially known as the croton bug, is a species of small cockroach, typically about 1.1 to 1.6 cm long. In color it varies from tan to almost black, and it has two dark, roughly parallel, streaks on the pronotum running anteroposteriorly from behind the head to the base of the wings. Although B. germanica has wings, it can barely fly, although it may glide when disturbed. Of the few species of cockroach that are domestic pests, it probably is the most widely troublesome example. It is very closely related to the Asian cockroach, and to the casual observer, the two appear nearly identical and may be mistaken for each other. However, the Asian cockroach is attracted to light and can fly like a moth, while the German cockroach cannot.
The Pennsylvania wood cockroach or Pennsylvanian cockroach is a common species of cockroach in eastern and central North America.
Parcoblatta virginica, the Virginia wood cockroach, is a small cockroach species of the genus Parcoblatta, measuring about a centimeter long as an adult.
Cockroaches are insects belonging to the order Blattodea (Blattaria). About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as pests.
The giant burrowing cockroach is also known as the rhinoceros cockroach, and Queensland giant cockroach. These cockroaches are native to Australia and mostly found in tropical and subtropical parts of Queensland. They are the world's heaviest species of cockroach and can weigh up to 30-35 grams and measure up to 7.5-8 cm (3.1 in) in length. It is a member of the family Blaberidae, which contains hundreds of species. It is part of the blaberid subfamily Geoscapheinae. It is prominent in the wild and can also be sold and kept as a pet.
The emerald cockroach wasp or jewel wasp is a solitary wasp of the family Ampulicidae. It is known for its unusual reproductive behavior, which involves stinging a cockroach and using it as a host for its larvae. It thus belongs to the entomophagous parasites.
Blaberus discoidalis, commonly known as the discoid cockroach, tropical cockroach, West Indian leaf cockroach, false death's head cockroach, Haitian cockroach, and drummer, is a cockroach native to Central America of the “giant cockroach” family, Blaberidae.
The death's head cockroach is a species of cockroach belonging to the family Blaberidae. It is often confused with the discoid cockroach, Blaberus discoidalis, due to its similar appearance. It is distinguished by jet black cloak-like marking on its wings and a skull-shaped, amber/black marking on its pronotum. The name death's head comes from the markings on the top of the pronotum: "cranii", which is Latin for "of the head", and "fer", meaning "carry" or "carrier". Due to their unique appearance and certain characteristics, they make an easy to care for pet or display insect for entomologists and hobbyists.
Insect physiology includes the physiology and biochemistry of insect organ systems.
Blaptica dubia, the dubia roach, orange-spotted roach, Guyana spotted roach, or Argentinian wood roach, is a medium-sized species of cockroach which grows to around 40–45 mm (1.6–1.8 in).
The speckled cockroach, lobster cockroach, or (small) cinereous cockroach is a species of cockroach in the family Blaberidae. It is the sole species in the genus Nauphoeta.
Eublaberus distanti, known as the six-spotted, four-spotted, four-spot, or Trinidad bat-cave roach or cockroach, is a primarily cave-dwelling Central and South American cockroach of the genus Eublaberus.
Parcoblatta uhleriana, the Uhler's wood cockroach, is a species of Parcoblatta native to the United States and Canada. It is a forest species also found in disturbed and urban environments. The male of the species flies freely, while the female does not fly.
Parcoblatta lata, the broad wood cockroach, is a species of wood cockroach native to the United States. It is one of the largest species of wood cockroaches.
Lucihormetica verrucosa is a species of giant cockroach in the family Blaberidae, commonly known as the warty glowspot cockroach. It is native to Venezuela and Colombia.
Diploptera punctata or the Pacific beetle cockroach is a species of cockroach in the family Blaberidae and subfamily Diplopterinae. It is one of the few cockroach species that is viviparous. Adults are chemically defended, having a modified tracheal gland and spiracle on each side which squirts quinones which can poison or discourage a predator.
Media related to Blaberus giganteus at Wikimedia Commons| Authority control databases: National |
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