Characteristic cockroaches, reproduction, feeding, species

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Jonah Lester

The cockroaches or blatodeans (Blattodea) are an order of insects that have a flattened body dorsoventrally and a well-developed pronotum, with the edges protruding towards the head. The first pair of wings may be absent, or present and leathery in appearance. In addition, they have multi-articulated frames.

Currently the group includes termites (Isoptera), a group of insects that derive from ancestral cockroaches, but in which an evolutionary convergence has occurred with other arthropods with which they are less related, such as ants, bees and wasps ( hymenoptera).

Blattodea. Taken and edited from: Cyron Ray Macey from Brisbane (-27.470963,153.026505), Australia [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)].

The order Blattodea groups some 6000 species, of which about 2/3 are represented by cockroaches and the like, while the remaining third is occupied by termites. Many of these species are omnivorous, while others are herbivorous, feeding mainly on cellulose thanks to the help of their intestinal flora..

Blatodeans are among the hardiest and most versatile species on the planet. They are capable of rapidly developing resistance to pesticides; They can survive for a long time practically without feeding or breathing and have cryptic habits that allow them to hide in the smallest and most unexpected places.

Some species are of sanitary importance, being vectors of numerous diseases that affect humans. In turn, termites are of commercial importance, affecting constructions made with wood and causing serious economic losses..

Article index

  • 1 Features
    • 1.1 Cockroaches
    • 1.2 Termites
  • 2 Taxonomy and classification
  • 3 Playback
    • 3.1 Cockroaches
    • 3.2 Termites
  • 4 Food
  • 5 Breathing
  • 6 most common species
    • 6.1 Common cockroach (Blatta orientalis)
    • 6.2 American cockroach (Periplaneta americana)
    • 6.3 German cockroach (Blatella germanica)
    • 6.4 Orange cockroach (Blaptica dubia)
    • 6.5 Reticulitermes flavipes
  • 7 References

Characteristics

Cockroaches

They have an oval and dorsoventrally flattened body. The head is usually small in size, with a large shield-shaped pronotum with expanded edges, extending towards the head. The antennae are filiform and multi-articulated, the eyes are compound and small in size..

The forewings are tegmina type, leathery in appearance, and may be absent in one or both sexes. The hind wings are extensive, fan-shaped, sclerotized and smaller than those of the first pair. The legs are thin, flattened and spiny, adapted for running.

They have a pair of lateral and multi-articulated rims in the posterior part of the abdomen. The eggs are placed in capsule-shaped and leathery-looking shells, called ootheca.

The size of the cockroaches is quite variable, with species that measure a few millimeters, up to the rhinoceros cockroach of Australian origin, which can reach 9 cm in length..

Termites

Small, soft-bodied organisms with wings of equal size, membranous and dehiscent. They have short and filiform antennae, made up of up to 33 trunks. The fences are small.

They resemble ants although they present a well marked polymorphism, with three different forms or castes: workers, soldiers and reproducers. The former are generally blind and sterile, with normally developed jaws..

Like the workers, the soldiers are blind and sterile, but they have highly developed jaws that they use in defending the colony. The reproductive forms, on the other hand, are winged and have well-developed and functional eyes..

Taxonomy and classification

Blattodea is an order of insects (class) located taxonomically in the subclass Pterygota, superorder Dictyoptera. The name of the taxon was proposed by Wattenwyl in 1882 and originally only included cockroaches..

Currently the order is composed of 13 families in three suborders: Blaberoidea, Corydioidea and Blattoidea. Termites are considered an infraorder (Isoptera) within the latter suborder.

This infraorder was previously considered an order, like Blattodea. However, fossil records and molecular biology studies have shown that they are actually highly modified relatives of today's cockroaches that evolved from common ancestors..

Taxonomists estimate between 6,000 and 7,500 species of blatodeans described to date, of which about a third are termites and the rest are "true" cockroaches..

Blattodea, family Ectobiidae. Taken and edited from: Vengolis [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)].

Reproduction

All Blattodea are dioecious, so they present sexual reproduction and separate sexes. They are hemimetabolic organisms, having an incomplete metamorphosis and three stages of development: egg, nymph and adult, also called imago. They lack the pupal stage.

Cockroaches

The degree of sexual dimorphism can vary depending on the species and is generally related to the presence or absence and size of the wings, size of the organism and shape of the abdomen..

Females release pheromones to attract the male and activate his sex drive. After courtship, copulation takes place, fertilization is internal and the female develops a variable number of eggs that she deposits all together in a capsule-shaped structure called the ootheca..

The female can deposit the ootheca immediately or retain it in the abdomen until just before hatching. Organisms hatch from the egg in the nymph stage, which can undergo several molts before reaching sexual maturity. Nymphs are similar to adults, but do not have wings and are not sexually mature.

The number of eggs per ootheca, as well as the number of ootheca that a female can deposit throughout her life will vary depending on the species. In some species, parthenogenesis may be present, that is, the ability to produce viable eggs without having been fertilized by the male..

This parthenogenesis can be obligate or facultative, in obligate parthenogenesis the population lacks males. In facultative parthenogenesis, there are males available in the population but in particular conditions the female can reproduce without the need to have been fertilized by a male.

Termites

Among termites, only the breeding caste is fertile, workers and soldiers are sterile. In some species there is a fourth caste, called pseudoergards, which are undifferentiated organisms that can transform into workers, soldiers or reproducers according to the needs of the colony..

In the colony, the reproducers are divided into two types: primary (king and queen) and secondary, which will only reproduce if the primary reproducers die or become ill..

Breeders are winged and quickly lose their wings after copulation. The queen's gonads will hypertrophy and the abdomen will increase many times its size..

Honeycomb or termite nest (Isoptera). Taken and edited from: ViajeroDelMundo2002 [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)].

Feeding

Xylophagous cockroaches (Cryptocercus spp.), like termites, feed on wood, in order to have this diet, these organisms have an intestinal flora with abundant microorganisms capable of digesting cellulose, because like the rest of the metazoans, cockroaches and termites are unable to digest this compound on their own.

The rest of the cockroaches are generalist omnivorous organisms, capable of feeding on anything from fresh or decaying plant foods to foods of animal origin. Some species can practice cannibalism.

Although they prefer foods rich in carbohydrates or fats, some species can even feed on dead skin cells, glue, toothpaste, sputum, hair, leather and a wide variety of substances, if conditions require it..

Even some species can tolerate long periods of starvation. For example, the American cockroach, which researchers have reported can survive up to three months without any type of food and up to a month without water..

Breathing

The blatodeos present a tracheal respiration like the rest of the insects. The hemolymph of insects does not transport oxygen, due to this they had to develop another mechanism that would guarantee that oxygen reached the different organs and cells of the body.

The tracheae are a set of tubes that communicate with the outside of the organism and that branch until they become tracheae that are associated with each cell of the insect. The tracheas open to the outside through holes called spiracles which are located in the lateral walls of the thorax and abdomen..

The spiracles open to the atrium, which has a valve activated by differences in the partial pressures of oxygen and carbon dioxide, additionally the walls of the atrium have mushrooms or thorns to prevent dust grains, small stones and other objects that could block the tracheal canal.

The tracheae do not collapse due to the presence of rings or thickening of their walls called tenidiums. Tracheoles have thin walls and are filled with fluid to allow oxygen to diffuse. Gas exchange between the tracheae and body cells is direct.

During the molting process, the tracheae are lost with the old exoskeleton, but this does not happen with the tracheae, so the new tracheae must join the old tracheae..

Most common species

Common cockroach (Blatta orientalis)

Also known as the black cockroach or oriental cockroach, it is a species native to the European continent that is currently distributed throughout the world thanks to the accidental spread during explorations and conquest trips by Europeans to other continents..

It is a medium-sized species, with organisms that reach up to 2.5 cm in length. It is sexually dimorphic, with a male with long wings and a slender body, and females with vestigial wings and a broader body..

It is dark brown to black in color, with nocturnal habits and inhabits sewers, drains, basements, warehouses, under bushes and other humid places without direct exposure to the sun's rays. The female reproduces every two months and her ootheca contains about 16 eggs, making it very difficult to eradicate.

American cockroach (Periplaneta americana)

Also known as the red cockroach, it is the largest of the common cockroaches, with specimens that can exceed 5 cm in length. It is native to Africa and the Middle East, but is currently distributed in tropical and subtropical areas of the entire world, some even inhabit areas of temperate climates.

Like most cockroach species, it is nocturnal and very fast. Live in basements, sewers, cracks in the walls, garbage cans, among other spaces. It is one of the most important pest species and can be the vector of numerous diseases that attack man.

The female is facultative parthenogenetic and lays up to 16 eggs in an elongated, leathery-looking ootheca. A female can deposit up to 10 ootheca throughout her life.

It is a very difficult pest to eradicate because it quickly acquires resistance to insecticides and defenses against biological controllers..

German cockroach (Blatella germanica)

This species of cockroach is also native to Africa and East Asia, but currently it has invaded practically all places on earth, being absent only in Antarctica.

It is a species of small size, as it generally does not exceed 16 mm. It lives in any type of human construction, from homes and restaurants to hospitals, it can even live in boats, airplanes and cars, which in turn serve as means of dispersal.

Blatella germanica it is very resistant to pesticides. In addition, it can feed on almost anything and the female carries the ootheca in the abdomen until moments close to hatching, which is why it is a very difficult pest to eradicate..

Orange cockroach (Blaptica dubia)

Also known as Guyana spotted cockroach or Argentine cockroach. It is a native species of the American continent and inhabits Central and South America. Presents greater abundance in French Guyana, Brazil and Argentina.

It is a medium-sized species, with organisms that do not exceed 4.5 cm in length. It presents sexual dimorphism, with winged males and females that only have vestigial wings.

The female is ovoviviparous and can have 20 to 40 young in each reproductive period. During reproduction, the female mates with only one male. The gestation period lasts just under a month and the young take between 4 and 6 months to reach sexual maturity.

Blaptica dubia It is very popular as a live food for reptiles and amphibians, as it has some advantages over other species of cockroaches and crickets such as: better digestible protein ratio, does not produce annoying noises, produces little odor and is easy to keep in captivity and to manipulate.

Reticulitermes flavipes

Species native to the United States that was introduced to central Europe in 1937 and quickly managed to settle, becoming a pest in countries such as France, Germany and Spain..

Macro of a termite (Isoptera). Taken and edited from: Sanjay Acharya [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)].

This is one of the termite species that generate the greatest annual economic impact in the United States. It is of subterranean habits, being able to build its nest more than 40 meters deep. This, and the fact that the female can lay between 5 thousand and 10 thousand eggs a day, make their eradication very difficult..

References

  1. Blattodea. On Wikipedia. Recovered from: en.wikipedia.org.
  2. W.J. Bell, L.M. Roth & C.A. Nalepa (2007). Cockroaches: Ecology, Behavior, and Natural History. JHU Press.
  3. A phantom destroyer. In Communicating Science. Recovered from: comunicaciencia.bsm.upf.edu.
  4. R.C. Brusca & G.J. Brusca (2003). Invertebrates. 2nd Edition. Sinauer Associates, Inc.
  5. C. Lira. Blatella germanica: characteristics, taxonomy, reproduction, feeding, biological control. Recovered from: lifeder.com.
  6. C. Lyre. American cockroach or red cockroach (Periplaneta americana): characteristics, taxonomy, reproduction, feeding, biological control. Recovered from: lifeder.com.

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