Flies, Gnats, and Mosquitoes • • • • • • • Mycetophilidae: fungus gnats (3000 spp.) Adults are found mostly in humid, forested areas The larvae feed mainly on fungi, although some species spin webs to capture insect prey and a few species are parasitoids of flatworms Drosophilidae: vinegar flies, pomace flies (2900 spp.) This family is best known for Drosophila melanogaster, the ubiquitous model organism for genetic research Although adults are commonly found around overripe fruit or on mushrooms, the larvae of this family have a variety of lifestyles, from saprophagy to parasitism and predation Psychodidae: moth flies (2700 spp.) The scavenging larvae of these flies are usually found in moist conditions, in soil, rotting wood, or other decaying vegetation Adults of one subfamily are blood feeders and transmit the disease leishmaniasis to humans Sarcophagidae: flesh flies (2500 spp.) Sarcophagid larvae are saprophagous, parasitoids, predators or commensals in the nests of solitary Hymenoptera The adults of some species are associated with filth Sphaeroceridae: lesser dung flies (2500 spp.) Larvae and adults of this family are commonly found on dung, carrion, and decaying organic material Stratiomyidae: soldier flies (2500 spp.) The adults of this family are often brightly colored and conspicuous on flowers The larvae are often found near water, in decaying organic material, or under bark They are saprophagous, herbivorous, or predatory Chloropidae: frit flies (2000 spp.) Larvae of chloropids have nearly every conceivable way of life, from scavenging to predation, parasitism and herbivory, although there are many more plant feeders in this family than the similarly diverse Phoridae Nematocerous Families The nematocerous families are the relatively primitive members of the Diptera, characterized by long, unconsolidated antennae consisting of many segments There are 26 families in this group and approximately 40,000 species included Many are associated with aquatic habitats and some, such as mosquitoes, black flies, and biting midges, are voracious blood feeders Brachycera Most Diptera belong to the Brachycera, a group characterized by the reduction or fusion of antennal segments to eight or fewer and by modifications to the larval head and mouthparts With about 80,000 described species, this group contains many of the best known flies, such as houseflies and fruit flies The lower Brachycera includes several lineages constituting approximately 30,000 species The larvae of most species are predatory, although there are a few parasitoid groups as well The most familiar are the large families Asilidae, Bombyliidae, Tabanidae, Dolichopodidae, and Empididae The Cyclorrhapha, with about 50,000 species, includes a few primitive lineages and the Schizophora The primitive groups are relatively small, with the exceptions of the large 493 families Phoridae and Syrphidae Within the Schizophora, there are a plethora of smaller acalypterate families that are rare, but many, such as the Tephritidae, Agromyzidae, Drosophilidae, Sphaeroceridae, and Ephydridae, are abundant and commonly encountered The Calyptratae includes the familiar houseflies, flesh flies, and blow flies as well as the speciose parasitoids of the Tachinidae Also included are a number of mammal parasites, including some truly bizarre, spider-like bat parasites in the Nycteribiidae and Streblidae Life History Diversity Larvae The larvae of flies are abundant and widespread in most terrestrial and aquatic habitats They are often encountered in soil (including sand), dead wood, dung, carrion, decaying vegetation, and among the refuse of social insect colonies Relatively few are found living exposed on vegetation, including some herbivorous tipulids and many aphidophagous syrphids Aquatic forms are found on the bottom and in the water column of lakes, streams, and ponds Larval Diptera are predators, scavengers, herbivores, parasitoids, or even true parasites Scavengers This is the lifestyle most commonly associated with Diptera larvae, especially those of the Brachycera More than half of the 128 families recognized herein have larvae that feed on decaying organic material or organic detritus Most receive their nutrition from bacteria and other microorganisms of decay, not from the main substance on which they are found They concentrate these organisms and other suspended particles with a sievelike pharyngeal filter Among the most obvious terrestrial scavengers are the larvae of blow flies (Calliphoridae) that are found on newly dead animal carcasses Early stages of decay are characterized by large numbers of calliphorid and muscid larvae, followed later by drosophilids, fanniids, phorids, piophilids, sepsids, sphaerocerids, and others as decay proceeds The fauna of buried carrion is different, with the calliphorids largely excluded Instead, the muscid genus Muscina, various phorids, and sphaerocerids predominate The fauna of carrion immersed in water has also been studied and found to differ from that on dry land There has been considerable study of the succession of scavenging Diptera larvae on dead animals, leading to the potential for their use in forensic entomology Decaying vegetable matter is also rich in scavenging Diptera, especially muscids, sphaerocerids, sciarids, and others Some muscids are obligate thermophiles, requiring the heat generated by the decay of large piles of compost Decaying seashore vegetation supports coelopids, sphaerocerids, and anthomyiids Rotting fruit is the food of drosophilids, stratiomyids, and some phorids In aquatic environments, many larval Diptera feed on small organic particles in the water or on the substrate Larvae of Culicidae and Simuliidae filter particles from the water with their brushlike labral fans