Family culicidae(mosquitoes)...entomology.18.oct.2010

Genera’s: Family contains more than 3,000 species and 34 generas. Out of these, there are 3 important genera of this family. Anopheles, Aedes and culex.

General Characteristics:

1. Species belonging to this family have cylinder shaped body, long legs, prominent eyes and bite is very painful.
2. Mosquitoes are important vectors of many protozoon, parasitic, viral and nematodal infections.Protozoon…plasmodium is transmitted by female anopheles mosquito.Viral………Eastern, Western and Venezuelon encephalitis are viral diseases transmitted by mosquitoes. Aedes Genus of mosauitoes spreads Dingy virus as well.Nematodal…Dirofilaria Immitis is transmitted by mosquitoes.
3. Food is composed of organic waste material. Habitat is from slow moving water to marshy areas.

Morphology

• Size of the species is 2-10mm. Species are having long narrow wings and wings head over the abdomen. Mouth parts are elongated and projecting forward. Mouth is called as proboscis which is adapted for piercing and sucking.
• Labium is also present. Labrum is present on the roof of the mouth. A pair of maxilla and mandibles is also present. Hypopharynx carries salivary duct. Liver anticoagulant is the issue.
• All the elements except labium enter the skin during feeding by the female forming a tube like structure through which blood is sucked.
• Maxilla and mandibles are absent or rudimentary in male mosquitoes.
• Antenna in both male and female is segmented and filamentous. Antenna in male is called as Plumos and in female is called as pilos.

Morphology of mouth part(proboscis)

Life Cycle:

1. Gravid Female after a complete blood meal lay 300 eggs on the surface of the water. Egg may be separate or in the form of the groups. Eggs are dark coloured with elongated or ovoid shape. Eggs are boat shaped in case of Anopheles mosquito.
2. Hatching of eggs is temperature dependent. It takes several days to several weeks. After hatching, larvae develop.
3. Maturation of larvae takes one week to several weeks. There are 4 larval stages…..L1,L2,L3,L4.
4. When larvae is fully developed, it is having compound eyes, long legs, a pair of antenna and prominent mouth brushes.
5. Larvae takes oxygen through spiracles. But in case of Aedes, respiration takes place through tube called as respiratory siphon.
6. From the larvae, pupa develops. Pupa is comma shaped and dark coloured. It contains cephalothorax and having long legs and very prominent eyes. Head can be seen. Respiration takes place through, respiratory trumpts.
7. In pupa, there are pad like extensions at abdomen which enable the pupa to move up and down in water. Pupa stage is very short.
8. From pupa, adult emerges. Adult is having very short life span. Adult flies 200m from the breeding place and then it dies. However, strong wind can carry them to several kilometers.

Pathogenesis: 
Mosquitoes cause different types of diseases in animals;

• Yellow fever.
• These transmit malaria which is the no.1 problem in the world.
• Cause arboviral infections which include eastern encephalitis, western encephalitis and venezuelon encephalitis.
• Dirofilaria Immitis(nematode) is transmitted by mosquitoes.
• Cause restlessness for animals.

Control:

1. Marshy areas should be properly drained off.
2. Destruction of the breeding places is necessary.
3. Introduction of some species of fish to eat mosquitoes.
4. Use of insecticides which include, organo chlorine, organic phosphate(neguvan, trichlorofen, asuntal and cumafax), carbamate and synthetic pyrethroid.