**9. Roles in the ecosystem**

only scavengers, and diseases such as cholera, yaws and dysentery can be trans-

Larvae of herbivores flies forage on plant tissues, some gall midges (Cecidomyiidae) bring creation of plant galls, some are parasites, predators or scavengers and this family primarily comprises the Hessian fly *Mayetiola destructor* Say. Numerous species of family Tephritidae (fruit flies) are agricultural pests, such

as the apple maggot *Rhagoletis pomonella* (Walsh). Most larvae of family Agromyzidae are leaf miners, some are stem and seed borers, and many

Scavenger larvae nourish in garbage, carrion, dung otherwise further biological material, pomace flies (Drosophilidae) larvae forage on rotting fruit, crane flies (Tipulidae) live in mud or soil, larvae of blow flies (Calliphoridae) nourish on carrion or garbage and include screwworm *Cochliomyia hominivorax* (Coquerel), midges (Chironomidae) aquatic larvae generally breath in mud and forage on biological material, and larvae of flesh flies (Sarcophagidae) usually nourish on carrion, but certain species can be source of human myiasis. Predatory larvae or adults predate on other insects as prey and specific flies produce predatory maggots that feed on other maggots. The predatory maggots of *Chrysomya rufifacies* (Macquart) (bluebottle) are covered with spiny protrusions which deter other predators. Families such as Asilidae (robber flies) are wideranging predators of other insects, Bombyliidae (bee flies) has predatory larvae and adults mimic to bees, Syrphidae (flower flies) (**Figure 5**) have larvae that are aphid predators and maximum adults mimic wasps or bees, and Empididae (dance flies) adults are also predatory. Parasitic larvae are parasitoids or parasites of insects and animals. Families like Tachinidae have several species that are important biocontrol agents and parasitoids of other insects, Hippoboscidae (louse flies) adults are bloodfeeding ectoparasites of mammals and birds, larvae of Sciomyzidae (marsh flies) parasitize snails and slugs, and Oestridae (warble flies and bot flies) larvae are

Anthomyiidae species are seed otherwise root maggots.

endoparasites of mammals as well as humans [47].

*(a) Robber fly, (b) Dance fly, (c) Flower fly, (d) Louse fly.*

**Figure 5.**

**16**

ferred on their mouthparts and feet.

*Life Cycle and Development of Diptera*

The prime advantage of flies originates from the parasitic species. They invade grasshoppers, caterpillars and other insects that damage to food plants. Certain flies are also important pollinators and aid to pollinate plants that are grown. Flies are likewise essential food basis for other animals that are valuable such as fish. Many fly larvae are part of the natural clean-up squad, helping to get rid of dung and dead animals.
