Diptera characteristics, classification, habitat, reproduction

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Simon Doyle
Diptera characteristics, classification, habitat, reproduction

The diptera (Diptera) are an order of insects that are part of the broad group of arthropods. Their name is due to the fact that they have a pair of wings. The insects that belong to this order are found practically in every corner of the planet, except the seas and oceans. Because of this, they are a successful group of animals when it comes to colonizing various environments..

This order is very broad, with more than 150 thousand species. Among the insects that can be found in the order Diptera we can mention flies, mosquitoes and horseflies. Some of these are of health importance because they are known vectors of certain pathologies such as yellow fever and dengue.

Copy of Diptero. Source: RimmaKhaz / CC BY (https://creativecommons.org/licenses/by/4.0)

Article index

  • 1 Characteristics of Diptera
    • 1.1 Head
    • 1.2 Thorax
    • 1.3 Abdomen
  • 2 Classification (types)
    • 2.1 Nematocera
    • 2.2 Brachycera
  • 3 Taxonomy
  • 4 Habitat and distribution
  • 5 Playback
    • 5.1 Life cycle
  • 6 Food
  • 7 Featured Diptera species
    • 7.1 Domestic musca
    • 7.2 Drosophila melanogaster
    • 7.3 Aedes albopictus
    • 7.4 Lucilia cuprina
    • 7.5 Aedes aegypti
    • 7.6 Scaptia can
  • 8 References

Diptera characteristics

Diptera are small animals, with an average length of about 2 mm. Because this order is made up of a large number of species, there are also insects that can reach 10 mm.

Taking into account that Diptera belong to the phylum of arthropods, their body is divided into several segments: head, thorax and abdomen..

Head

The head is independent of the thorax, it is separated from it by a thinning and it has a lot of mobility.

Likewise, it can be of various shapes: oval, hemispherical, triangular or round. Here on the head are the antennae. These are made up of several segments, known by the name of artejos. The number of antennae trunks is variable.

In the head are also the organs of vision. They can be simple eyes or compound eyes. The latter are made up of a large number of ommatidia. The ommatidia are the units that are characterized by having photoreceptor cells and pigment cells.

Detail of the head of a Diptera. Source: JJ Harrison (https://www.jjharrison.com.au/) / CC BY-SA (https://creativecommons.org/licenses/by-sa/1.0)

In the case of simple eyes, also called ocelli, there are generally three in number and they are located in a triangular position on the top of the head..

Here it is also possible to find sows and it is believed that they have a sensory function.

Chest

Diptera thorax is divided into three parts: prothorax, mesothorax and metathorax. From each segment a pair of legs is born. The most developed segment is the mesothorax, so it occupies a greater amount of space.

The legs have different morphologies, depending on the species. There are long ones, as well as robust and short. They are made up of five segments (artejos). From distal to proximal, these are: tarsus, tibia, femur, trochanter and coxa.

When it comes to wings, they have a pair. These are of the membranous type. There are species that, despite being included in this order, lack wings.

Abdomen

It is also variable in shape. There are species in which it is wide and others in which it is very narrow. It is also segmented. The less evolved the species, the more abdominal segments it has.

Here in the abdomen are the respiratory spiracles. These are orifices into which the small windpipes flow through which gas exchange takes place..

In the terminal part of the abdomen, are the genital structures of the animal, which are quite particular for each species.

Classification (types)

The order Diptera is classified into two suborders: Nematocera and Brachycera.

Nematocera

To this suborder belong the gnats and mosquitoes. Their distinctive feature is that they present filiform antennae that are made up of several segments. In the case of male specimens, the antennae have a feathery appearance.

In addition to this, their larvae have a normal-looking head and their pupa is of the obteca type. They have a long maxillary palp that, like the antennae, is composed of a varied number of segments.

This suborder includes seven infraorders: Tipulomorpha, Psychodomorpha, Ptychopteromorpha, Culicomorpha, Blephariceromorpha, Axymyiomorpha, and Bibionomorpha. These infraorders group a total of 35 families.

Brachycera

This suborder includes insects known as the common fly and the fruit fly. Their main characteristic, and what differentiates them from the Nematocera suborder, is that their antennae are small in size. In addition, the antennae do not have a filiform shape..

Some of the members of this suborder are ectoparasites of some animals. Many others have a carnivorous type of diet, while a small group is scavenger.

Six infraorders are located in this suborder: Asilomorpha, Muscomorpha, Stratiomyomorpha, Tabanomorpha, Vermileonomorpha and Xylophagomorpha.

Taxonomy

The taxonomic classification of Diptera is as follows:

  • Domain: Eukarya
  • Animalia Kingdom
  • Phylum: Arthropoda
  • Class: Insecta
  • Subclass: Pterygota
  • Infraclass: Neoptera
  • Order: Diptera

Habitat and distribution

Diptera are widely distributed throughout the planet. They have managed to colonize practically all types of environments and ecosystems, except the marine ones. However, they are frequent inhabitants of the coasts, both of fresh water bodies and brackish water..

These insects are quite versatile, so they can even be found in places with perpetual snow, such as in the Himalayas..

From a biogeographical point of view, Diptera are more abundant in the Pelearctic region. This area is the largest on the planet and is made up of the European continent, northern Asia, part of the Middle East and the extreme north of Africa.

However, this distribution does not indicate that there are not enough dipteran species in the other regions. Yes there are, only that many species that remain unknown have not yet been properly described..

Reproduction

The type of reproduction observed in most species of Diptera is sexual. This is characterized because it requires the fusion of two gametes or sex cells, one male and the other female..

However, there are a few species that reproduce asexually. This process does not involve the interaction between two parents, but the descendants are generated from a single parent. The asexual reproduction method observed in Diptera is parthenogenesis.

Lifecycle

The life cycle of Diptera is holometabolic. This means that it undergoes a complete metamorphosis with four stages: egg, larva, pupa and adult..

Egg

The eggs have different morphology, depending on the species. They are elongated, round or oval. They are very small in size, not exceeding one millimeter. However, there are some exceptions where the eggs can measure up to 2mm..

The colors are also variable, although they are frequently pale in color. They can be placed in groups or isolated. The number of eggs that each female lays is variable, and can be from a few (6 or 8), up to thousands of eggs..

The female lays her eggs in different places, depending on the habitat in which she develops. For example, in the case of mosquitoes, the eggs are deposited in the water. In this sense, mosquito eggs have a structure known as a float, which allows them to stay afloat and not fall to the bottom.

Life cycle of a Dipteran. Source: Alan R Walker / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

The incubation time of the eggs is variable. This is determined by the species and by environmental conditions, such as temperature and humidity..

When the required time elapses, the eggs hatch and larval forms emerge from them..

Larva

Because the Diptera class is made up of many species, its larvae have distinctive characteristics. However, broadly speaking, two types of larvae can be distinguished.

Some are worm-like with a head-like structure, called the cephalic capsule. This type of larvae also has a normal chewing apparatus. It is typical of lower species of Diptera.

On the other hand, there are larvae that do not have the cephalic capsule, in such a way that they look like worms without any type of anatomical differentiation. These larvae are typical of the more evolved Diptera, such as those belonging to the Brachycera suborder..

Diptera larvae are apodal, that is, they do not have articulated legs that allow them to move correctly through the substrate in which they develop. Despite this, there are species in which their larvae may have some sucker-like appendages or hooks to adhere to the substrate or to the host (if they are parasites)..

Pupa

In Diptera there are two types of pupae: obtecta and alibi. The pupae obtained are characterized by the fact that the future appendages of the adult animal are visible on their surface, while in the coarctate pupae these appendages cannot be visualized.

The pupae obtained are typical of the lower Diptera, while the aliased pupae correspond to the upper Diptera..

Once the adult individual is fully developed, it proceeds to emerge from the pupa. To achieve this, he uses a structure that he has on his head, similar to a balloon. This structure is inflated, pressing against the pupa, until it manages to open a hole, through which it exits.

Adult

This is the shortest phase in the life cycle of Diptera. Their average life span is variable. There are species that only live for a few hours, while there are others that can live up to months.

The role of the adult individual is related to the mating process and the position of the eggs.

Mating is a process that in some species involves some type of courtship ritual. For example, there are species in which the male offers the female a kind of gift (a prey) before copulation..

Fertilization is internal, which means that physical contact is required between the female and the male. The latter deposits the sperm inside the female's body. In Diptera there are also some particular cases with regard to copulation. There are species in which both males and females are integrated into what is known as a copulating cloud and there they come into contact and fertilization occurs..

After copulation, the female proceeds to deposit the eggs on some surface, where they are protected.

Feeding

The diet in the Diptera is very varied. There are species in which the adult individual does not feed, as well as there are others in which the larvae do not have the need to feed because they develop inside the body of the female..

In species whose adult individuals do feed, great diversity can be seen in terms of the food they prefer. There are some that feed on the nectar of flowers, as well as many others that are blood-sucking, that is, they feed on the blood of mammals. In this case, they have specialized structures, which allow them to adhere to the host's body surface and pierce it.

On the other hand, the feeding predilection of the larvae also varies. There are herbivorous, that is, they feed on plants or algae, depending on the habitat in which they are found..

There are also carnivorous ones, which means that they eat meat. Finally, there are some that are scavengers and feed on dead organic matter, which is why they are frequently found in corpses..

Featured Diptera species

Domestic musca

Musca domestica. By Housefly_musca_domestica.jpg: Muhammad Mahdi Karimderivative work: B kimmel / GFDL 1.2 (http://www.gnu.org/licenses/old-licenses/fdl-1.2.html)

It is known as the common fly. It is widely distributed throughout the globe. They are approximately 8 mm long. Their eyes, which are compound, have a red coloration.

It lives very closely with the human being, constituting a problem for this, since it is the vector of many diseases such as typhoid fever, tuberculosis, salmonellosis and cholera, among others..

Drosophila melanogaster

Drosophila melanogaster specimen. Source: Hannah Davis / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)

It is commonly known as the fruit fly. It is a famous species because it was the working material of Thomas Morgan, who laid the foundations of what is known as sex-linked inheritance..

They present a marked sexual dimorphism. The females are larger than males. In addition to this, they have a slightly longer abdomen, which ends in a point. While the male's abdomen ends in a rounded shape.

They have a fairly short life cycle, of about 21 days, and feed on fruits that are in the process of fermentation..

Aedes albopictus

It is known as the tiger mosquito due to the characteristic striped pattern on its body. It is found in the Asian continent, but it can also be found in other regions of the world such as the American continent..

Sometimes it can be a vector for diseases such as West Nile virus, dengue fever and yellow fever. When it comes to their diet, there are differences between males and females. While the latter feed on the nectar of the flowers, the females feed on the blood of some mammals such as humans.

Lucilia cuprina

It is commonly known as the Australian sheep fly. It can be found in various parts of the world such as America and Africa, in addition, of course, Australia.

In the medical field, this insect is quite useful. In the forensic part, it is of great help to be able to date the time of death of a corpse, since it is one of the first insects that deposit their eggs in corpses.

Equally, Lucilia cuprina It is an insect that some doctors apply for debridement therapies, that is, removal of dead and infectious skin. For this reason, its use in medicine contributes to eliminating the risks of gangrene..

Aedes aegypti

It is known as the “white-legged” mosquito because of the characteristic white bands that surround its legs. It is found throughout the world, although it is particularly abundant in places where hygienic conditions are precarious..

This mosquito is a recognized vector of important diseases such as dengue, yellow fever, Zika and chikungunya, among others. It feeds on blood, which it ingests when it bites its victims, mainly mammals.

Scaptia can

It is a dipterous insect typical of the south of the American continent, specifically Argentina and Chile. Feeds on the blood of mammals, including humans.

This fly has a characteristic yellowish and reddish color on its abdomen. They are considered very annoying for people who live near their natural habitats, since they are constantly biting them.

References

  1. BÁEZ, M. 1988. 37 Diptera: 503-519. In Barrientos, J.A. (Coord.): Bases for a practical course in Entomology. Spanish Association of Entomology, Faculty of Biology, Salamanca.
  2. Brusca, R. C. & Brusca, G. J., (2005). Invertebrates, 2nd edition. McGraw-Hill-Interamericana, Madrid
  3. Carlés, M. and Hjorth, T. (2015). Diptera order. IDEA SEA Magazine. 63
  4. Courtney, G., Pape, T., Skevington, J. and Sinclair, B. (2009). Biodiversity of Diptera. Chapter in the book: Insect Biodiversity: Science and Society. Blackwell Publishing.
  5. Curtis, H., Barnes, S., Schneck, A. and Massarini, A. (2008). Biology. Editorial Médica Panamericana. 7th edition.
  6. Hickman, C. P., Roberts, L. S., Larson, A., Ober, W. C., & Garrison, C. (2001). Integrated principles of zoology (Vol. 15). McGraw-Hill.

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