Flies, Gnats, and Mosquitoes (Order Diptera)
Dipterans, also known as the "true flies," may be recognized by the possession of only two wings instead of the four that other adult insects have. In Diptera, the hindwings have been modified into tiny, clublike halteres, which are used as organs of balance. Most dipterans lack mandibles, and adults are common visitors to flowers, where they drink nectar with their spongelike or sucking mouthparts. Adult female dipterans of many species are blood suckers and require one or more blood meals for egg production. The larvae of many dipterans are aquatic or feed in anaerobic decaying matter; others feed on plant material or are predaceous on other insects. One family (Tachinidae) is particularly important as parasites of caterpillars; the larvae feed internally until the entire host is consumed. Dipteran larvae are legless and maggotlike except for specialized aquatic forms, such as mosquito larvae.
Crane flies,Tipulaspp. (Family Tipulidae). (Fig. 7.25) Crane flies have the appearance of very large mosquitoes but are completely harmless. They occur at elevations up to 13,000 ft (4,000 m).
Mosquitoes,Anophelesspp. (Family Culicidae). (Fig. 7.26) Mosquitoes are common in wet areas, such as along the Owens River or boggy areas at higher elevations. Members of this genus are the principal vectors of malaria in California.
Robber Flies, (Family Asilidae). (Fig. 7.27) Robber Flies are common and easily recognized by their stout thorax, wings, and legs, and by their behavior of perching in exposed positions and sallying forth after flying prey. They are very diverse in the White Mountains at all elevations.
Figure 7.25
Crane Fly (Tipula sp.).
Figure 7.26
Mosquito (Anopheles sp.).
Figure 7.27
Robber Fly.
Hover Flies (Family Syrphidae). Hover Flies are commonly seen visiting flowers. Many species look very much like bees or wasps. They also commonly hover in midair, holding a fixed position relative to the surrounding vegetation, and abruptly changing position when approached. Larvae of some species are caterpillarlike and feed on aphids and small herbivorous insects. Some species occur at elevations as high as the top of White Mountain Peak.
Common Hover Fly, Metasyrphus aberrantis . (Plate 7.1) Occurs on flowers from 6,000 to 10,000 ft (1,800 to 3,100 m). The larvae crawl on plants and eat aphids and other small insects. They are legless, yet manage to cling to vegetation very efficiently.