- Mosquitoes - Classification
- Class :
- Insecta
- Order :
- Diptera
- Group :
- Nématocera
- Family :
- Culicidae
Definition
Mosquitoes represent a highly varied group, including over 3,000 species spread throughout the world, adapted to most climates. 3 genera are predominant: Culex, Aedes and Anopheles. The female mosquito is hematophagous (blood-sucking), and therefore a potential vector of diseases. Mosquitoes are the primary disease vector in the world: malaria, chikungunya, dengue, yellow fever, etc.
Morphology
Mosquitoes are insects of the order Diptera (they have 2 wings. Di = 2 and ptera = wing). They measure approximately 15 mm. The female is slightly larger than the male. The body is divided into 3 parts: the head, the thorax and the abdomen. The head includes: 2 eyes, 1 pair of antennae, which allow the mosquito to guide itself: odour, touch, taste and a proboscis with which the female bites. The thorax, composed of 3 segments, has 3 pairs of legs, 1 pair of wings and 1 pair of halteres. The genital appendices are located on the abdomen.
Life cycle
The mosquito's life cycle includes 2 phases:
- an aquatic phase: larval and pupal development.
- aerial phase: in which the adult flies and breeds.
Having bitten and taken in blood, the female lays its eggs (a few days later) on the surface of still water. The site of egg-laying varies depending on the species: clean water, polluted water, tree hollows, jam jars, etc.
Depending on the species, eggs may take from a few hours to several months to hatch. During a dry period, some eggs slow their development and can remain viable for several years. Once hatched, the eggs release a larva that will go through several developmental stages before producing a flying adult. Only adult mosquitoes are able to fly; their range of activity may extend over several kilometres. In favourable temperature conditions, the development cycle from egg to adult stage may take under 10 days. The female mosquito prefers a temperature between 15 and 30°C and moist areas. An adult mosquito may live for several days to several months, depending on the species.
Feeding habits
Mosquitoes feed on flower nectar.
Bites
Only the female bites vertebrates (including humans), from which it takes blood, which contains the proteins necessary for the maturation of eggs. Not all mosquitoes bite humans; this varies depending on the species. For example: Culiseta longiareolata: birds; Culex hortensis and Culex impudicus: frogs and toads. The female bites during the reproductive period.
The female mosquito finds its target by the odour that the animal gives off. It is particularly sensitive to carbon dioxide and the lactic acid given off by the skin when it breathes. Body temperature and moisture can also play an important role: the higher the body temperature, the more likely the mosquito will be to bite.
It is also not recommended to move when mosquitoes are present, because that attracts them.
When the female mosquito bites, it injects saliva at the same time as it draws blood. This saliva contains anticoagulants, which cause an allergic reaction in humans, responsible for small red itching bumps. In certain countries, mosquitoes can also carry diseases. When it bites, an infected mosquito injects its target with the pathogenic agent: for example: Anopheles, carriers of malaria (pathogenic agent: Plasmodium), Aedes, carrier of dengue and chikungunya (pathogenic agent: virus).
Example of transmission cycle of pathogenic agents / ex: mosquito-human-mosquito