Division Lower Diptera
Division Lower Diptera
Compiler and date details
31 December 1997 - E.-M.E. Bugledich, CSIRO Entomology, Canberra, Australian Capital Territory, Australia, with subsequent updating of some families as indicated
The Diptera, or true flies, is a speciose order containing all those insects in which the adult has only one pair of wings, situated on the meso- (second) thoracic segment. The 'wings' of the third (meta-) thoracic segment are modified as balancers or halters. The name 'fly’ is attached to the common names of many flying insects, such as whitefly, caddisfly, alderfly and mayfly, none of which are dipteran or 'true' flies. Common true flies include the mosquitoes, midges, gnats, black flies, crane flies, horse flies, hover flies, house flies and blow flies.
The higher classification conventionally has the order Diptera divided into a phylogenetically basal suborder, the Nematocera, and a more derived suborder, the Brachycera. All recent studies concur in finding that the Nematocera are an unnatural grouping—technically the monophyletic Brachycera are related only to a subordinate part rather than the totality of the Nematocera. This renders the Nematocera paraphyletic. However, for practical subdivision of the Diptera into manageable units for cataloguing the Australian fauna, the term Nematocera (adj. nematoceran) is retained. In this group are placed all dipterans with an antennal flagellum comprising four or more freely articulating flagellomeres, lacking apical fusion into an arista or style, and generally with at least three palpal segments.
Many families of Nematocera are virtually worldwide in distribution, and the representation in Australia of the dominant families is unexceptional. However, a few smaller families with more restricted global distributions are missing from Australia, namely the Deuterophlebiidae, Axymyiidae, Pachyneuridae, Syneuridae, Canthyloscelidae and Ptychopteridae, and one notable family of restricted distribution is present, the Perissomatidae. In Australia, taxonomic effort has been applied unevenly across the Nematocera, with more emphasis particularly on the medically significant Culicidae, Ceratopogonidae, Phlebotominae (Psychodidae) and Simuliidae. Demand from the limnological research community for biological monitoring purposes has led to taxonomic study concerning several aquatic nematoceran families such as the Chironomidae. Conspicuous by their absence from an Australian research agenda has been the Cecidomyiidae (agriculturally significant flies), the environmentally important Mycetophilidae and the immature stages of many families, including the speciose and ecologically diverse Tipulidae and Ceratopogonidae.
The order Diptera ranks amongst the largest in the Insecta, and within it is demonstrated a very wide range of adult and larval biologies. Many nematocerans have aquatic immature stages, including those of many families of medical significance in the adult stage, such as mosquitoes, black flies and many biting midges. Because of this public health significance, some of their immature stages may be as well known as the mature stages of other insects. Nematoceran families with filter feeding aquatic larvae include, for example, planktonic taxa (Chaoboridae, Culicidae), feeders in the surface meniscus (Dixidae), and sessile ones attached to the substrate (Simuliidae, Blephariceridae). Amongst other aquatic dipteran larvae, detritivory and saprophagy in benthic depositional substrates is very common (many Chironomidae, Tipulidae, Psychodidae). Some Chironomidae, Ceratopogonidae, Tipulidae, Culicidae and Chaoboridae have predatory aquatic larvae. Amongst the specialised aquatic habitats are thin water films (the hygropetric or madicolous zone) that provides a home for some grazers (Thaumaleidae, some Ceratopogonidae, Chironomidae and Psychodidae) and plant container habitats (phytotelmata) (many Culicidae, Corethrellidae, some Psychodidae, some Ceratopogonidae and some Chironomidae). Marine habitats such as rockpools, estuaries and mangroves are used by a few Tipulidae and Chironomidae and some Ceratopogonidae (whose adult females make themselves obnoxious by their human-biting habits).
Although the aquatic habitat is utilised by many nematoceran larvae, many others can be found in a wide variety of terrestrial and semi-terrestrial locations. For example, many Sciaridae and Mycetophilidae (sensu lato) develop in fungal hyphae and in sporocarps (fruiting bodies), and general saprophagy is seen amongst Trichoceridae, Scatopsidae, Anisopodidae, Bibionidae and many Tipulidae. Certain species amongst the latter families can utilise decomposing wood and other plant-derived vegetative matter. Living plant material is less widely utilised, although the very speciose Cecidomyiidae includes many gall formers, some of which can cause economic levels of damage to horticulture and crops. Sporadically amongst many other families there are specialist herbivores, notably in the root-feeding Bibionidae.
The Diptera are holometabolous, with usually 3–6 larval instars followed by a pupal stage (pupation) where tissues are reorganised into the adult form. Some aberrant life histories that involve repression of the adult stage (paedogenesis) occur amongst certain Cecidomyiidae and Chironomidae. The larval stage tends to be of relatively long duration, and is the stage in which most feeding takes place. Recognition of larval Diptera is not easy because of the diversity of shapes and forms, but all are united by the lack of any segmented thoracic legs. However, there are representatives of other insect orders that lack thoracic jointed legs, but these larvae tend to be sluggish (such as endoparasites) and often rather swollen with undirected movement. Aquatic dipteran larvae, in contrast, are usually active and more slender or maggot-like.
In shape, aquatic nematoceran larvae range from slender and eel-like ceratopogonids to the almost maggot-like larger tipulid larvae. The head is usually distinct, darkened and protruding anteriorly, but the head capsule may be incomplete posteriorly and partially retracted into the anterior thorax (some Tipulidae) or reduced to a remnant skeletal structure mostly retained within the anterior thorax (Cecidomyiidae). The body may be smooth, or with a wide range of welts and tubercles. Legs, when present, are unsegmented prolegs which may have a crown of crochets or claws. Movement may be by swimming (aquatic taxa) or by maggot-like contraction and relaxation of segments to anchor on the substrate (many terrestrial taxa). The distribution of larval spiracles can be valuable in making identifications: some species are apneustic, others are metapneustic or amphipneustic.
Nematoceran pupae tend to be of short duration, there being few cases of pupal diapause. Reconstruction of the tissues can be as rapid as less than an hour is some small Chironomidae. Pupation may take place in aquatic taxa within the water or less commonly outside the aquatic environment in damp marginal habitats. Less is known about pupation in terrestrial environments, but the departure of mycetophiloid last-instar larva from deliquescent fungal sporocarps in search of more suitable pupation site frequently is observed.
On the Fly, the interactive Atlas and Key to Australian fly families, by Hamilton et al. 2006, is available from CBIT, University of Queensland.
This volume was compiled at CSIRO Entomology, Canberra, and my thanks are extended for provision of facilities and especially to the staff of the Black Mountain Library for their very generous assistance. Funds for the compilation of this work and for preparation of some of the figures were provided by the Australian Biological Resources Study.
Many of the illustrations in the published work (Bugledich, E.-M.A., 1999) are by Karina Hansen McInnes to whom thanks and appreciation are extended. Others are reproduced from The Insects of Australia with permission from CSIRO Entomology and Melbourne University Press.
Among people who gave advice freely during the preparation of this volume are Don Colless, Jo Cardale, Peter Cranston, Gunther Theischinger, Mary Carver, Dick Norris, Neal Evenhuis, David Ride, Ray Gagné, Alan Clift and the late Tony Watson. I thank them all, and my family as well.
The author and editors thank the following colleagues for reviewing one or more sections of the manuscript: Art Borkent, Don Colless, Peter Cranston, Derek Duckhouse, Alan Dyce, Ray Gagné, Peter Kolesik, Loïc Matile and Günther Theischinger. The editors, Alice Wells and Keith Houston, are thanked for editorial advice, for checking of data and checking of the final manuscript. Ha Diep's close attention to detail in the final copy is greatly appreciated.
The information on the Australian Faunal Directory site for the Nematocera is derived from the Zoological Catalogue of Australia database compiled on the Platypus software program. It incorporates changes made to the work published on 21 June 1999 as (Bugledich, E.-M.A., 1999)
Relevant aspects of the nomenclatural history of the Nematocera are discussed beneath each family in the following text. However, some general points ought to be made in this introduction. There is no (nor ever can be) fixity of rank, nor absolute comparability of ranks across this or any other taxonomic group. Different workers will continue to propose elevation of subordinate groups for reasons that today relate more to ideas on phylogeny than to earlier beliefs in degree of morphological divergence. However, consensus amongst all workers is rare and debate continues. In Bugledich (1999), a conservative approach was adopted concerning the Tipulidae (q.v.), but the fragmentation of the Mycetophilidae (q.v.) was accepted.
The major part of the Catalogue was authored by Eva-Marie Bugledich. Wendy Lee made the principal contribution to the Culicidae and Peter Cranston and Jon Martin assisted with the Chironomidae. Chironomidae have been updated from time to time to add data provided by Peter Cranston, and in the Ceratopogonidae, the genus Culicoides was updated to include additional taxa included in Dyce et al. (2007).
Distribution data in the Directory is by political and geographic region descriptors and serves as a guide to the distribution of a taxon. For details of a taxon's distribution, the reader should consult the cited references (if any) at genus and species levels.
Australia is defined as including Lord Howe Is., Norfolk Is., Cocos (Keeling) Ils, Christmas Is., Ashmore and Cartier Ils, Macquarie Is., Australian Antarctic Territory, Heard and McDonald Ils, and the waters associated with these land areas of Australian political responsibility. Political areas include the adjacent waters.
Terrestrial geographical terms are based on the drainage systems of continental Australia, while marine terms are self explanatory except as follows: the boundary between the coastal and oceanic zones is the 200 m contour; the Arafura Sea extends from Cape York to 124 DEG E; and the boundary between the Tasman and Coral Seas is considered to be the latitude of Fraser Island, also regarded as the southern terminus of the Great Barrier Reef.
Distribution records, if any, outside of these areas are listed as extralimital. The distribution descriptors for each species are collated to genus level. Users are advised that extralimital distribution for some taxa may not be complete.
Colless, D.H. & McAlpine, D.K. 1991. Diptera (Flies). pp. 717-786 in CSIRO (ed.). The Insects of Australia. A textbook for students and research workers. Melbourne : Melbourne University Press Vol. 2 pp. 543-1137.
Krivosheina, N.P. 1986. Family Anisopodidae (Rhyphidae, Phryneidae). pp. 330-332 in Soós, Á. & Papp, L. (eds). Catalogue of Palaearctic Diptera. Vol. 4. Sciaridae-Anisopodidae. Amsterdam : Elsevier 441 pp.
History of changes
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