True flies (Diptera)

Abstract The Order Diptera (true Pies) comprises an ecologically and morphologically diverse assemblage of holometabolous insects. A number of morphological characters unite this lineage (1–3), the most recognizable one being the extremely reduced, knob-like, metathoracic wings, or halteres (Fig. 1). themajority of true Pies also bear specialized sponging mouthparts that diBer markedly from the chewing mouthparts found in most insects. Approximately 150,000 species of Diptera have been described in 180 families, although total species diversity undoubtedly exceeds twice that number (1, 2, 4). Myriad species of Diptera are economically important vectors of human and animal pathogens (e.g., Culicidae) and many are destructive to crops and livestock (e.g., Tephritidae and Oestridae, respectively). Flies are also important ecologically as predators, decomposers, parasitoids, and pollinators (5, 6). Here we review the relationships and divergence times of major events in dipteran evolution, including the origin of the order and its constituent suborders, infraorders, and families. Traditionally Pies have been divided into two suborders: Nematocera (“thread-horn” Pies) and Brachycera (“short-horn” Pies). 7is division was based primarily on characters of the adult antennae and larval head capsule (1, 2, 7). Although a number of shared-derived characters support the monophyly of the Brachycera, the Nematocera is now widely regarded as a paraphyletic assemblage of infraorders, or suborders (8), from/within which the Brachycera originated (7, 9, 10). For a detailed overview of the current state of Diptera systematics, see Yeates and Wiegmann (1, 2).