**14. Biting Diptera**

Biting flies are two-winged external insects that feed actively on the blood of vertebrate hosts in the morning or evening and at night or day, and their biting is of a considerable nuisance. Their irritating bites could transmit pathogenic organisms that cause devastating loss of human and animal lives. The biting insects suck blood from humans and animals, and their biting is of a significant annoyance. More importantly, they are carriers for a number of organisms producing diseases and result in expiries on a huge scale. The most significant set of biting Diptera is mosquitos that have a slender and long body, and needle-shaped long piercing mouthparts. Others comprise phlebotomine sandflies, blackflies, tsetse flies, biting midges, stable flies and horseflies (tabanids), which normally have smaller biting mouthparts and additional robust bodies. The last three sets as vectors of human disease are of limited importance [64].

#### **14.1 Mosquitoes (Culicidae)**

Mosquitos diverge from other biting Diptera in having long needle-shaped mouthparts, a long slender body and long legs. The wings occasionally have noticeable outlines of scales. The adult insects measure between 2 and 12.5 mm in length. Certain species bite at night or in morning and evening, whereas others feed out of doors or during the day time indoors. There are several important genera of mosquitoes and key genera include *Culex, Aedes* and *Anopheles.*

Males of the numerous species do not suck blood but feed on plant juices. The females usually mate only once, but produce eggs at intervals throughout their life and so most female mosquitos require a blood-meal. The ingestion of a blood-meal and the coinciding eggs development take 2–3 days in tropics, however longer in temperate regions. The gravid females look for appropriate places to lay their eggs, afterwards which another blood-meal is taken and another batch of eggs is laid. This practice is repetitive till the mosquito perishes. The mosquito life cycle involves eggs that are laid mainly in water. In some species, eggs are laid signally, while in others, these are laid joined together in rafts. Dependent on the species, a female lays eggs between 30 and 300 at a time. Various species directly lay their eggs on water surface either singly (*Anopheles*) otherwise fixed jointly in floating rafts (*Culex*). Particular species (*Aedes*) lay their eggs just above the water link otherwise on wet mud and only when flooded with water these eggs hatch. If left dry, these can keep on viable for several weeks. Larvae (wigglers) hatch and feed on aquatic material, pupate (become tumblers) and eventually emerge as adults. Adult females may live for several months [65, 66].

Among the mosquitos there are two groups that suck human blood and may transmit disease. The anophelines; the genus *Anopheles* is best known for its role in transmitting of malaria, but in some areas it can also transmit filariasis. The culicines comprise the genera *Aedes,* vectors of dengue, yellow fever and other viral diseases and from time to time of filariasis; *Culex,* vectors of filariasis and various viral diseases; *Mansonia*, transmitter of *brugian filariasis*; and *Sabethes* and *Haemagogus*, spreaders of yellow fever in forests of Central and South America. Mosquitos *Aedes*, *Anopheles* and *Culex* may be differentiated from each one by way as presented in **Figures 8**–**12**. The best valuable features to distinguish anophelines from other

### *Typical Flies: Natural History, Lifestyle and Diversity of Diptera DOI: http://dx.doi.org/10.5772/intechopen.91391*

mosquitos are size of palps that is equivalent to proboscis; whereas these generally at rest retain their abdomen and mouthparts in a straightforward stripe at an angle to relaxing place; the angle differs within species and in various circumstances it is nearly erect to surface. In south Asia, vector of malaria *Anopheles culicifacies* Giles, is an exemption by keeping body nearly equivalent to surface. As per its name proposes, this one superficially looks similar to mosquito *Culex*. A number of mosquitoes, including *Psorophora*, *Aedes*, *Mansonia*, *Culex* and *Anopheles* spp., are important parasites of domestic animals. When the blood-feeding females are present in large numbers, they cause stress to animals and produce severe anemia [67, 68].
