Tiger mosquito characteristics, habitat, feeding, diseases

4962
David Holt

Aedes albopictus It is a mosquito that belongs to the well-known genus Aedes, of the Culicidae family. It is also known as the tiger mosquito, which is due to the striped pattern on its body.

It was first described in 1895 by the British entomologist Frederick Skuse. Initially it was only found in certain areas of Asia, but now, thanks to the possible action of human beings, it has been introduced in other regions of the American, European and African continents. It is considered a harmful invasive alien species.

Aedes albopictus. Source: James Gathany, CDC [Public domain]

As with other species of the genus Aedes, Aedes albopictus it can act as a vector for some viruses such as dengue, yellow fever, and West Nile virus. Taking this into account, its control has become a matter of public health, since these diseases in some cases can be fatal.

Article index

  • 1 Taxonomy
  • 2 General characteristics
  • 3 Morphology
  • 4 Habitat and distribution
  • 5 Life cycle
    • 5.1 Mating and fertilization rites
    • 5.2 Eggs
    • 5.3 Larvae
    • 5.4 Pupa
  • 6 Food
  • 7 Transmitted diseases
    • 7.1 - Yellow fever
    • 7.2 - Dengue
    • 7.3 - West Nile Fever
  • 8 Treatment
  • 9 Prevention
  • 10 References

Taxonomy

The taxonomic classification of Aedes albopictus is the next:

-Domain: Eukarya

-Animalia Kingdom

-Phylum: Arthropoda

-Class: Insecta

-Order: Diptera

-Suborder: Nematocera

-Family: Culicidae

-Gender: Aedes

-Species: Aedes albopictus.

General characteristics

Aedes albopictus it is an organism that, like all members of the Animalia kingdom, are considered eukaryotes. This means that their cells have a central structure, which is delimited by a membrane and is called the cell nucleus. Within this is the genetic material of the animal forming its chromosomes.

In the same vein, this mosquito is a multicellular organism, since it is made up of several types of cells, each of which fulfills a specific function..

Regarding its embryonic development, it is feasible to affirm that Aedes albopictus it is a triblastic animal. This is so because in its development the three germ layers become evident: ectoderm, mesoderm and endoderm, from which each and every one of the tissues that make up the adult animal are formed. They are also coelomed, which implies that they have an internal cavity called a coelom..

If an imaginary line is drawn along the longitudinal axis of the species, two exactly equal halves are obtained, so it has bilateral symmetry.

From a reproductive point of view, Aedes albopictus it is an organism that reproduces in a sexual way, with internal fertilization and indirect development. Finally, they are oviparous, because they hatch from eggs.

Morphology

This mosquito is small, measuring approximately 10 millimeters at most. Its body is dark in color, which can range from black to reddish. The body has horizontal white stripes. However, the distinctive element of this species of mosquito is a longitudinal white line that covers its head and part of the torso..

As with most arthropods, it has a segmented body, from which three pairs of jointed legs emerge. These are characterized by having white bands.

Aedes albopictus. The longitudinal white line is clearly visible. Source: James Gathany, CDC [Public domain]

Although males and females share this morphology, there is a significant difference between the two. Females have a kind of trunk that is known by the name of proboscis, which has the function of helping to pierce the skin of the animals to which it bites to absorb their blood. Because males do not feed on blood, they do not have this structure.

Finally, like every animal that flies, Aedes albopictus presents wings. These are a pair, long and slender and come off the torso of the animal.

Habitat and distribution

Aedes albopictus It is a mosquito native to the Asian continent, specifically the eastern area. However, it can also be found in some regions of America, to which it has been introduced through various mechanisms..

Regarding the characteristics of the habitat in which this animal develops, it can be said that this is a "tree" mosquito, due to which it is found in places where there is abundant vegetation. For the time of its reproduction, it does so in small bodies of water, which are surrounded by plants.

Geographical distribution of Aedes albopictus. Source: Moritz UG Kraemer, Marianne E Sinka, Kirsten A Duda, Adrian QN Mylne, Freya M Shearer, Christopher M Barker, Chester G Moore, Roberta G Carvalho, Giovanini E Coelho, Wim Van Bortel, Guy Hendrickx, Francis Schaffner, Iqbal RF Elyazar, Hwa-Jen Teng, Oliver J Brady, Jane P Messina, David M Pigott, Thomas W Scott, David L Smith, GR William Wint, Nick Golding, Simon I Hay [CC0]

However, this mosquito can also be found in urban ecosystems. In these areas it is mainly found in places where there is accumulated water, such as bird baths, flower pots and tires with stagnant rainwater..

Biological cycle

The biological cycle of Aedes albopictus it is very similar to the mosquito that causes yellow fever, Aedes aegypti. It is made up of four stages: egg, larva, pupa and adult mosquito.

Aedes albopictus reproduces sexually. This means that the exchange of genetic material is required and therefore the fusion of a female and a male gamete..

Rites of mating and fertilization

These mosquitoes have a curious mating rite, which consists of emitting a buzz. This buzzing has a different frequency in females and males..

Flapping is another element that plays an important role during the mating process. Under normal conditions, the flapping of females is 400 cycles per second, while that of males is 600 flaps per second. Well, when they are in the process of mating, both rhythms are paced in unison and reach 1200 cycles per second..

When this happens, both mosquitoes mate in a copulation process in which the male deposits his sperm in the female's spermatheca. Later, inside the female's body, the fertilization process occurs. This is that each one of the spermatozoa that were deposited in the spermatheca fertilizes the ovules of the female mosquito. In this way the eggs are formed to start the life cycle.

Eggs

Once the eggs are formed, the female must deposit them in places that have the minimum required humidity and temperature conditions so that they can develop successfully. In this sense, they deposit them in containers containing water, where they can adhere to their smooth walls. Eggs do not need to be immediately covered by water.

However, due to the action of external agents such as rain, the container fills up. As soon as the eggs are covered by water, they hatch, thus releasing the larvae..

Larvae

In this species of mosquito there are four larval stages. The difference between one and the other lies in the size, which is increasing as each state happens. The larvae feed on the organic particles that are suspended in the water.

Fourth instar larvae are approximately 7mm long and pupate after 72 hours..

Pupa

The pupa remains immobile, without feeding, a little below the surface of the water. Despite this, it is in this phase that the animal experiences the greatest amount of morphological changes, developing structures such as legs, some systems and wings, among others..

The time a mosquito lasts in this stage varies in females and males. In the latter it is 48 hours, while for females it can last up to 60 hours. Finally, when the animal is completely ready, it breaks the protective cuticle and manages to leave the pupa, beginning its life as an adult..

Feeding

Power supply Aedes albopictus varies in each gender. The males feed on the nectar of the flowers, which is why they are known as nectivores. Because of this, they go from one flower to another, taking their nectar.

On the other hand, females are much more aggressive than males, since they feed directly on the blood of vertebrate animals, especially mammals and birds. This is why females are considered blood-sucking. In addition, thanks to their eating style, they are responsible for the transmission of diseases.

Transmitted diseases

Aedes albopictus, like many other species of the genus Aedes, it is a vector of some diseases such as yellow fever, dengue and in some isolated cases, West Nile virus.

- Yellow fever

This is an infectious disease caused by a virus, which requires a vector to be inoculated in humans. In this sense, mosquitoes of the genus Aedes, as well as those of the genre Haemagogus they fulfill this function.

It is a disease that is confined mainly to the tropical zone of the planet, being South America and Africa its most frequent locations. In general, this disease is closely related to precarious health conditions, since they are what allow the breeding sites of the mosquitoes that transmit it to proliferate..

Symptoms

Yellow fever is a disease that has two variants: a mild one and one that can be much more aggressive and even fatal, so the symptoms and their intensity vary as well. Some of them are:

-Intense headache.

-Very high fever.

-Digestive problems such as nausea, vomiting, and sometimes diarrhea. They can often be accompanied by blood.

-Muscle pains.

-Jaundice (yellow skin and mucous membranes).

-Neurological problems such as seizures and delirium.

-Spontaneous bleeding.

-Cardiology symptoms involving heart rhythm irregularities.

If the disease is not treated in time, the symptoms can exacerbate and worsen the patient's state of health, even reaching multi-organ failure, in which a large number of organs are affected, thus making absolute recovery difficult. When this stage is reached, which is known as the toxic stage, the chances of the patient dying are very high.

- Dengue

Dengue is a disease caused by a virus, of the arbovirus type. There are five serotypes of this virus. In order to infect humans, this virus requires a vector that in 100% of cases are mosquitoes belonging to the genus Aedes.

This disease is common in tropical and subtropical areas of the planet. It is mainly abundant in Southeast Asia, as well as in Latin America and the Caribbean islands. As with yellow fever, it is strongly linked to risky hygiene conditions.

The symptoms that people with dengue have are varied. Although there are several types, people who suffer from it do not necessarily have to experience them all, the disease being easily diagnosable. The main symptoms of dengue are the following:

-High fever.

-Intense headache.

-Intestinal symptoms: nausea and vomiting.

-Swollen lymph nodes.

-Skin rash (rash).

-Severe retroocular pain.

-General discomfort.

-Bone and joint pain.

When people are affected by the classic form of dengue, these symptoms subside within a few days. However, when they are infected with the aggressive variant of dengue, their blood vessels are often affected and they bleed. This is due to the decrease in blood cells that are responsible for clotting, platelets.

- West Nile fever

This is a disease caused by the West Nile Virus. Although its most frequent vector is the Culex pipiens (common mosquito), in exceptional cases Aedes albopictus it can also participate as a vector in its biological cycle.

It is a disease that mainly attacks mammals such as horses and humans. It is native to the African continent, specifically the sub-Saharan area. However, it has not remained in this geographical area, but cases have also been located in Asia, Western Europe and the rest of Africa. Just about 20 years ago, the first case was registered in North America, specifically in New York City..

In general, people who are infected by this virus rarely show symptoms. When they do, they may present the following:

-Intense headache.

-High fever.

-Generalized skin rash.

-Swelling of the lymph nodes.

-General discomfort.

-Muscle and joint pain.

The clinical picture can resolve itself. However, in a small percentage of the affected population, the symptoms do not remit and the virus even attacks the central nervous system, mainly affecting the brain tissue and the meninges (layers of tissue that surround the organs of the central nervous system)..

When the virus affects the brain, it causes its inflammation, generating a pathology known as encephalitis. On the other hand, when the affected tissue is the meninges, then we speak of meningitis. In either case, the result can be fatal. When not, there may be serious sequelae for life.

Treatment

Although mosquito-borne diseases Aedes albopictus are caused by viruses, there is no specific treatment for each virus. Of course, a treatment is applied, however, it is aimed at treating the symptoms.

This is why the drugs that doctors normally prescribe are antipyretic and anti-inflammatory. Of course, rest is essential for the patient's recovery..

In the case of people who are afflicted with serious forms of the diseases, such as the so-called dengue hemorrhagic fever or Nile virus encephalitis, they should receive a little more aggressive treatments, such as blood transfusions and even procedures of surgical type.

However, it is important to clarify that aggressive forms of these diseases are much less common than the classic ones..

Prevention

To prevent mosquito-borne diseases Aedes albopictus, what should be done is to avoid the bites. In this sense, you can use creams or sprays that are applied to the surface of the skin and function as repellants..

Likewise, it is also important to limit or avoid the reproduction of the mosquito. To achieve this, certain measures must be taken, such as: avoiding storing containers with stagnant water in the home; Do not store stacked objects such as garbage in places such as the patio, since rainwater can accumulate there and keep rain drains uncovered so that water does not accumulate there.

However, in the case of yellow fever, there is also a vaccine, the effect of which lasts for 10 years. This has proven to be one of the most effective measures to prevent the spread of the disease, especially in those who travel to places where it is very common..

References

  1. Berti, J. (2014). Aedes albopictus: Bionomics, ecology, distribution and role in the transmission of Arbovirus in Venezuela. Lecture given at the XII Dr Arnaldo Gabaldón Scientific Conference. December 2014.
  2. Brusca, R. C. & Brusca, G. J., (2005). Invertebrates, 2nd edition. McGraw-Hill-Interamericana, Madrid
  3. Curtis, H., Barnes, S., Schneck, A. and Massarini, A. (2008). Biology. Editorial Médica Panamericana. 7th edition.
  4. Hawley, W. (1989). The biology of Aedes albopictus. Journal of the Americam Mosquito Control Association Supplement. 4
  5. Hickman, C. P., Roberts, L. S., Larson, A., Ober, W. C., & Garrison, C. (2001). Integrated principles of zoology (Vol. 15). McGraw-Hill.
  6. Marín, J., Rueda, J. and Alarcón, P. (2014). Ten years of "Aedes albopíctus”In Spain: Chronicle of an announced invasion. Avedila Veterinary Laboratory. 67
  7. Rey, J. and Lounibos, P. (2015). Ecology of Aedes aegypti Y Aedes albopictus in America and disease transmission.

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