**11. Life of Diptera**

Blow flies (family Calliphoridae) are metallic blue, green or black in color, noisy in flight and resemble to the housefly. A female of blowfly at one time lays up to 300 eggs and with many females visiting any corpse, number of maggots may be immense. For instance, on a 156 g piece of meat, 48,562 maggots are initiated after 24 hours exposure. On the other hand, since this has been inadequate food to withstand them, only 231 flies lastly emerged. In hot weather, helpful to fly growth,

The growth times of fly vary depending on the species and the temperature, but generalized life cycle typically takes 3–4 weeks depending on the species. Eggs are found in clusters of up to 300 and time takes 1 day from laying to hatching. Initially, first instar larva feeds on fluid oozed from body then migrates into body and takes 1 day from hatching to first molt. Larva of second instar travels around in maggot mass and from first molt to second molt takes 1 day. Larva in third instar moves still in mass, significantly increases in dimension and takes 2 days from second molt to pre-pupa. Pre-pupa drifts away from the corpse for seeking an appropriate pupation location (commonly in soil), does not forage, converts into pupa and takes 4 days from pre-pupa to pupa. Pupa exist within puparium, does not feed and transformation from pupa to adult fly emergence takes 10 days. Upon emergence from pupa, adults fly mate, feed on protein from body fluids, and lay eggs on corpse and emergence to egg laying takes 2 days [50, 51]. The life table

(**Table 1**), shows an estimated development times (in hours) at 20°C of certain

A characteristic life-cycle of dipteran follows a short-term egg stage (generally days or on occasion greatly longer), larval and pupal phases of variable length, and an adult stage lasting for a few to many hours or days. The period of larvula is shortest, while the last larval stage that is key feeding form is much lengthier. Totally, larval instars share an identical habitat, however various Chironomidae make sure to have planktonic larvulae and benthic later-instars. A lot of marine Diptera is univoltine categorized by quick development. In cyclical system with cold season, immature insects generally in an initial instar, diapause till environments are satisfactory. Postdiapause development regularly initiates with increasing spring hotness, even though algal accessibility and photoperiod may be associated. Period after egg-hatch to adult beginning differs among and occasionally contained by species, such as does presence of further generations (bivoltine to multivoltine).

maggots can devour 60% of a human body in less than a week.

*An average approximate development times (in hours) of some specific fly species at 20°C.*

**Fly species Egg First**

*Life Cycle and Development of Diptera*

*Hydrotaea rostrata*

*Chrysomya rufifacies*

**Table 1.**

**instar**

**Second instar**

*Calliphora augur* no eggs 24 24 60 96 336 23 *Calliphora stygia* 24 48 24 48 96 324 23 *Lucilia cuprina* 26 33 33 24 114 324 23 *Lucilia sericata* 21 31 26 50 118 240 20

**Third instar**

48 60 60 36 144 324 28

24 36 36 72 72 168 17

**Prepupa** **Pupa Total time (days)**

fly species.

**18**

**10. Phenology**

Most flies remain active throughout the year and many of them live less than a year. Many fly species survive the winter only as eggs. Others survive as pupae and a few survive as larvae or adults. Like all insects, they do not truly hibernate, but enter a state of diapause, which slows down their development and appetite, until temperatures rise and they become active again. Unless they hibernate, adult flies do not usually live very long, often only a month or two and sometimes just few days or weeks. Flies usually spend most of their lives as a larva or a pupa, and mostly spend the winter as adults in cracks and openings, and become active in spring. Flies are eaten by many predators, so very few of them live as long as they can.

### **12. Classification of Diptera**

Diptera has worldwide distribution, diverse habitats and diets in both larvae as well as adults, while sizes range 1 mm–7.5 cm. Among differentiating taxonomic structures, wings are utmost distinct feature of Diptera, and these comprise a couple of functional front wings and condensed rear wings termed as halteres that help as balancing organs. With the exception of male scale insects, Diptera only have hind wings adapted into halteres. The thorax contains a complete mesothorax occupied with muscles that operate to forewings. The single couple of wings as well differentiate to Diptera from other insects so-called flies (dragonflies, caddisflies), whereas the posterior halteres isolate Diptera from other insects having single pair of wings (certain beetles and mayflies).

Separation of Diptera into suborders is established on wing venation and structure of antennae. Additional key features are chaetotaxy and arrangement of strong bristles in several fixed locations, and given specific or group names. Split-up of Diptera into families is based on habits (feeding), and habitats of adults and larvae. Species and genera are differentiated by details of head structure and profile of head, degree of separation and shape of eyes, and legs shape and proportions of segments. Abdominal shape generally defines distinctive appearance of a genus, however it is hard to express because the shape differs as the insect is starving, well fed or gravid (viviparous flies, for instance, tsetse fly) [53].

Diptera order is traditionally divided into two suborders distinguished by the differences in antennae, Nematocera (flies with multi-segmented antennae) and Brachycera (flies with stylate antennae) having about 110 families divided between them although one suborder Cyclorrhapha is non-monophyletic (flies with aristate antennae) [54].

The Nematocera species are recognized by their elongated bodies and manysegmented, often feathery antennae as represented by mosquitoes and crane flies. The Brachycera have rounder bodies and much shorter antennae. The Nematocera comprises commonly delicate and small insects having lengthy antennae such as crane-flies, mosquitoes, midges and their relatives. The Brachycera contains more robust and compact flies with small antennae [55].

**Family Cecidomyiidae** (gall midges): Minute flies rarely seen as adults; larvae shapeless, tunnel in plant tissues, form plant galls, collapse foliage, stalks, roots;

**Family Psychodidae** (moth flies): Minute, wings hairy; frequently visible alone in kitchens, windows over sinks; larvae generally aquatic; several larvae plentiful in

**Family Phlebotomidae** (sand flies): Thoroughly interrelated to Psychodidae; female adults blood sucker, transmit intestinal and dermal leishmaniasis, sand fly

**Family Chironomidae** (nonbiting midges): Correlated to biting midges, however females not blood sucker; larvae marine; essential for fish food; adults fly close

**Family Simuliidae** (black flies, buffalo gnats): Minute, humpbacked, antennae short; females blood sucker, transfer parasitic worms causing 'river blindness'; under skin form nodules; aquatic larvae, fastened to stones, freshwater crustaceans

**Family Culicidae** (mosquitoes): Elongated; small; prominent proboscis; long palpi; recognized best through scaly wings; various females blood sucker, transport human diseases (Culicini transmit filariasis, yellow fever, viral encephalitis, den-

Antennae flagellum always mostly joined to a compound third segment, left over diminutive segments practice a bristle-like or stumpy style arista; wing anal cell narrowed, nearly usually closed on or earlier to wing border; palpi rarely have more than three segments, usually one or two, detained frontward (porrect); larvae head usually well-defined, mandibles travel parallel or vertically, may not be opposed;

**Family Stratiomyidae** (soldier flies): Colorful flies, found relaxing with wings closed on vegetation; males occasionally in air dance; sometimes larvae extended, active, carnivorous (*Stratiomys*), aquatic; others in decomposing foliage (*Hermetia*). **Family Rhagionidae** (snipe flies): Unremarkable, relax on vegetation usually; certain females (*Symphoromyia*) blood sucker; maximum larvae in soil otherwise in water (*Atherix* females make egg-laying flights); certain form pits in soil, such as

**Family Pantophthalmidae** (timber flies): Big, outmoded flies, found currently only in South American tropical forests; wood-boring larval grubs from time to time

**Family Tabanidae** (deer flies, horse flies): Short flies having large heads, eyes colored brilliantly; certain females (*Tabanus*, *Chrysops*, *Haematopota*) blood sucker, pests of livestock; several primitive genera only feed on flowers; larvae in wet soil or

**Family Asilidae** (robber flies): Adults in flight clip other insects, suck blood; vary in sizes as of a few mm to 8 cm (lengthiest than other flies); distinctive 'moustache' of hairs possibly defends eyes from fly's victim damage; larvae in wood

**Family Bombyliidae** (bee flies): Scaly, hairy; resemble to bees superficially, in similar way hover over flowers; often patterned brightly, by rubbing scales pattern

mud, either carnivorous (*Haematopota*,*Tabanus*) or vegetarian (*Chrysops*).

**Family Ceratopogonidae** (biting midges): Minute, usually wings spotted (*Culicoides*); female adults annoying by bite, blood sucker, transmit certain parasitic

certain horticulture and agriculture pests.

*DOI: http://dx.doi.org/10.5772/intechopen.91391*

*Typical Flies: Natural History, Lifestyle and Diversity of Diptera*

worms; *Forcipomyia* blood sucker of insects.

or underwater vegetation, filter feeders.

**12.2 Suborder Brachycera**

ant lions (*Vermileo*).

injury profitable wood.

or soil; feed on several diet.

**21**

gue; Anophelini transfer malaria); aquatic larvae and pupae.

through a rectangular slit adults escape from pupa (Orthorrhapha).

dirt sedimentation containers.

fever.

to water.

In older classifications of Brachycera, two Divisions have been recognized; Cyclorrhapha and Orthorrhapha. Orthorrhapha contains brachyceran flies devising obtect simple pupae, for instance, robber flies and horse flies, and Cyclorrhapha comprises brachyceran flies having enclosed pupae within tough puparium. Cyclorrhapha is additionally separated in two sets built on absence or presence of ptilinum and fissure linked to head. Ptilinum is an eversible pouch above antennae base used during emergence of adult fly to push on and open anterior end of puparium. The Aschiza has an absence of ptilinum and it though exists in Schizophora.

Nematocera in general are soft-bodied and slender flies having long antennae containing of several segments alike, palpi of many segments noticeably often drooping, and wings bear numerous longitudinal veins, however in the middle of wing generally lacking the conspicuous discal cell. When present, the anal cell is broadly exposed. Insects in Brachycera are generally fairly big flies, of stout body, antennae short, however occasionally showing traces of more than three segments, wings generally with a very thorough venation and with a discal cell, and palpi neither more than two-segmented nor conspicuously drooping. Cyclorrhapha includes the most highly specialized Diptera, mostly of short and stout build, with short antennae and many bristles. In recent decades by a suite of workers, the customary assemblages of Diptera have been analytically revised within a cladistic framework starting with the great dipterist Willi Hennig. Consent has emerged that several of traditional categories such as Orthorrhapha, Aschiza and Nematocera are not natural sets (they are paraphyletic). In other arguments these categories contain a group of basal lineages from that of other (monophyletic) categories (Brachycera, Cyclorrhapha and Schizophora) stand up. Recently, efforts to frame a monophyletic classification of Diptera have achieved pace, however to date, no overarching consensus has been gotten [56–58].

Order Diptera all together is a group of familiar insects that has traditionally been divided into three suborders [59–62]:-

#### **12.1 Suborder Nematocera**

Antennae contain flagellum, pedicel and scape having many segments alike; maxillary palpi bear in excess of three segments, frequently pendulous; anal cell open in wing; larvae generally with distinct head; mandibles opposed horizontally.

**Family Tipulidae** (crane flies or daddy long legs): Body, legs, wings elongated; slow-flying; larvae within soil (leather jackets), rotten wood, mud, moss, marine, fresh water, seaside.

**Family Mycetophilidae** (fungus gnats): Delicate, slim; dip in wet shaded dwellings, between rotting foliage.

**Family Sciaridae** (dark-winged fungus gnats): Related to fungus gnats, however extra dense, more frequently indoors.

**Family Bibionidae** (march flies): Solid, well-armored flies; spurs on legs strong; frequently plentiful over spring blossoms; larvae found within soil, on occasion tangled in a mass close to plant roots.

**Family Scatopsidae** (minute black scavenger flies): Analogous to march flies, more frequently indoors.

**Family Cecidomyiidae** (gall midges): Minute flies rarely seen as adults; larvae shapeless, tunnel in plant tissues, form plant galls, collapse foliage, stalks, roots; certain horticulture and agriculture pests.

**Family Psychodidae** (moth flies): Minute, wings hairy; frequently visible alone in kitchens, windows over sinks; larvae generally aquatic; several larvae plentiful in dirt sedimentation containers.

**Family Phlebotomidae** (sand flies): Thoroughly interrelated to Psychodidae; female adults blood sucker, transmit intestinal and dermal leishmaniasis, sand fly fever.

**Family Ceratopogonidae** (biting midges): Minute, usually wings spotted (*Culicoides*); female adults annoying by bite, blood sucker, transmit certain parasitic worms; *Forcipomyia* blood sucker of insects.

**Family Chironomidae** (nonbiting midges): Correlated to biting midges, however females not blood sucker; larvae marine; essential for fish food; adults fly close to water.

**Family Simuliidae** (black flies, buffalo gnats): Minute, humpbacked, antennae short; females blood sucker, transfer parasitic worms causing 'river blindness'; under skin form nodules; aquatic larvae, fastened to stones, freshwater crustaceans or underwater vegetation, filter feeders.

**Family Culicidae** (mosquitoes): Elongated; small; prominent proboscis; long palpi; recognized best through scaly wings; various females blood sucker, transport human diseases (Culicini transmit filariasis, yellow fever, viral encephalitis, dengue; Anophelini transfer malaria); aquatic larvae and pupae.
