Disclaimer & Copyright Notices; Optimized for the MS Internet Explorer

Order Diptera

(Two-winged or true flies)

Soil & Water Conservation Society of Metro Halifax (SWCSMH)

Top- Family: Ceratopogonidae (biting midges, no-see-ums); Bottom- Family: Chironomidae (true midges); View: lateral

Updated: October 09, 2013

Linnean system of hierarchical classification (Williams & Feltmate, 1992):

Superphylum Arthropoda

(jointed-legged metazoan animals [Gr, arthron = joint; pous = foot])

Phylum Entoma

Subphylum Uniramia

(L, unus = one; ramus = branch, referring to the unbranched nature of the appendages)

Superclass Hexapoda

(Gr, hex = six, pous = foot)

Class Insecta

(L, insectum meaning cut into sections)

Subclass Ptilota

Infraclass Neopterygota

Introduction

The Diptera, or true flies, are a large order of endopterygote Neoptera. It is estimated that the order contains about 200,000 species, worldwide, although only just over half of these have been described. Clearly, the Diptera have been much more successful than their presumed sister-group, the Mecoptera (scorpionflies) which has less than 400 described species.

Aquatic dipterans represent some of the best known insect forms, including mosquitoes, black flies, midges, crane flies and horse flies, many of which are the most troublesome of all insect pests, particularly in terms of human health and economics. Despite this, many groups of aquatic Diptera play pivotal roles in the processing of food energy in aquatic environments and in supporting populations of fishes and waterfowl.

Approximately 10% of all dipteran species are aquatic in their larval stage. Eggs and pupae of these species are also aquatic, whereas adults are always terrestrial.

Some 32 families of Diptera contain species whose larvae are either aquatic or semiaquatic. These are contained in two suborders, the more primitive Nematocera (literally translated as "thread-like horn", and referring to the nature of the adult antenna), and the Brachycera ("short horn"= short antenna). Detailed coverage will be confined (in separate files) to five groups that are important from ecological and/or human welfare perspectives, namely the Chironomidae (midges), Culicidae (mosquitoes), Tipulidae (crane fly), Simuliidae (black fly), and Chaoboridae (phantom midges).

Life History

Egg-laying behavior is diverse in the aquatic members of this holometabolous order. Some scatter eggs just below the surface on vegetation or on mineral substrates; others deposit eggs in gelatinous masses at, below, or above the water surface on emergent objects.

The number of larval instars varies among dipterans; nematocerans have 4, cyclorrhaphans have 3, and orthorrhaphans may have 8 or 9. Larval stages as short as several weeks and as long as two years have been reported, depending on the species, water temperature, and food conditions. The pupal stage lasts approximately two weeks, except in species that overwinter as pupae. Most species overwinter as hibernating eggs, as larvae, or, rarely, adults. Some arctic chironomid larvae coil up in cocoons and overwinter under freezing conditions.

Females of many species are anautogenous, requiring a blood meal to acquire enough protein to produce eggs (Ceratopogonidae, Culicidae, Simuliidae, Tabanidae), and some are vectors of animal or human diseases or both.

Mating of many nematocerans and some brachycerans (e.g., Tabanidae) occurs in swarms. Some species swarm over sand or cow dung or many objects that serve as swarm markers; others swarm around their hosts for both mating and feeding. After mating occurs, females leave the swarm to oviposit. Males of some empidids offer nuptial gifts (usually food) to their mates and copulate while the females are eating.

Most aquatic dipterans are univoltine, but under favourable conditions some may complete more than one generation a year. Some species may take two or three years to complete development in colder climates. One arctic chironomid is reported to have a seven-year life cycle.

Habitat and Distribution

It is evident that the Diptera or two-winged flies are by far the most diverse order of insects in fresh water; they are in fact the most diversified of any major taxon of freshwater organisms. The aquatic legless larvae of the Diptera certainly outnumber, in both individuals and species, all the other aquatic insects taken together. The separation of the Diptera, as potential or actual inhabitants of deep water, from the other orders of immature aquatic insects is justified by the fact that an elaborate classification of lake types has been built upon the ecology of the deep-water Chironomidae (true midges) and their associated organisms. The question as to why, among all the aquatic insects with gills, this family of Diptera has alone significantly exploited the depths of lakes is of considerable interest. Because they are the only order that has become fully emancipated from restriction to quite shallow littoral waters, the problems that the Diptera present may often be quite different from those posed by other aquatic insects. Though some, such as the mosquitoes, have larvae that surface for air, the existence of dermal respiration often involving some sort of blood gill is usual in the order and has evidently permitted it to extend far into the profundal region of bare sediment. The generally small size, at least in the lacustrine Diptera, is doubtless important in this invasion.

Dipteran larvae occur in almost every conceivable aquatic habitat, from the bracts of pitcher plants (Culicidae: Wyeomyia), tree holes (e.g., Chironomidae and Culicidae), saturated soil, and mud puddles, to streams, ponds, large lakes, rivers, and even the marine rocky intertidal zone. Stratiomyids have been recorded from geyser-fed thermal pools that reach temperatures up to 49 deg. C, and ephydrids from natural seeps of crude petroleum. Dipterans are found in rushing streams (Blephariceridae, Deuterophlebiidae), stagnant pools, hot springs, and frozen sediments. The only aquatic habitat where dipterans have not been recorded is the open ocean.

They are classified as clingers, sprawlers, planktonic swimmers, burrowers, climbers, and miners.

Families of Diptera that contain aquatic or semiaquatic species, together with descriptions of larval habitats (Williams & Feltmate, 1992)

Family	Distribution and Habitat
Suborder - Nematocera
Infraorder Tipulomorpha
Superfamily Tipuloidea
Tipulidae	(crane flies)- fast & slow-flowing streams & rivers; springs; hygropetric habitats; ponds & lakes, esp. in shallow water; fresh & brackish water marshes; wet moss; tree holes & other phytotelmata; marine intertidal zone; saturated soil; temporary pools; floodplains
Infraorder Psychodomorpha
Superfamily Blephariceroidea
Blephariceridae	(net-winged midges)- fast-flowing, cool streams, generally at high altitude
Deuterophlebiidae	(mountain midges)- fast-flowing, cool streams, generally at high altitude
Nymphomyiidae	among moss in cool, fast-flowing streams
Superfamily Tanyderoidea
Tanyderidae	(primitive crane flies)- shallow water at margins of stream & rivers
Ptychopteridae
Ptychopterinae	drainage ditches, esp. those contaminated with manure; beaver ponds
Bittacomorphinae	(phantom crane flies)- very shallow woodland pools
Superfamily Psychodoidea
Psychodidae	(moth flies)- fast streams, esp. margins; littoral zone of lakes, esp. in detritus; marine beaches
Infraorder Culicomorpha
Superfamily Culicoidea
Dixidae	(dixid midges)- sheltered regions of streams, also in detritus; pond & lake at margins or under surface film
Chaoboridae	(phantom midges)- lakes in profundal, littoral or open water zones; boggy pools; temporary fresh waters; small springs, esp. limnocrenes
Culicidae	(mosquitoes)- ponds & lakes; pools and slow sections of streams & rivers; bogs; marshes; woodland pools; temporary waters; salt marshes; marine rockpools; phytotelmata; water tanks; small container habitats e.g. tin cans, tires, bottles, coconut shells
Superfamily Chironomoidea
Thaumaleidae	(solitary midges)- hygropetric habitats; small, cold streams, esp. margins; wet moss
Simuliidae	(black flies)- fast-water regions of streams & rivers; wave-swept, littoral zone of large lakes
Ceratopogonidae	(biting midges, no-see-ums)- littoral & open water zones of lakes, also at margins esp. in algal mats; streams & rivers, esp. margins & in detritus; tree holes; temporary pools; moist soil; salt marshes; marine beaches; some species associated with pollution
Chironomidae	(midges)- most types of waterbody, including intertidal rockpools & coral reefs; moist soil; phytotelmata; dung
Suborder - Brachycera
Infraorder Tabanomorpha
Superfamily Stratiomyoidea
Stratiomyidae	(soldier flies)- streams & rivers, esp. margins; littoral zones of ponds & lakes, esp. around submerged & emergent macrophytes; hot springs
Superfamily Tabanoidea
Rhagionidae	(snipe flies)- moist soil & moss in woodlands
Pelecorhynchidae	small, foothill streams, on sand substrates
Tabanidae	(horse & deer flies)- wetlands; littoral zones & margins of ponds & lakes; damp soil; slow-water regions of streams & rivers; tree holes; marine beaches; estuaries
Athericidae	streams & rivers
Infraorder Asilomorpha
Superfamily Empidoidea
Empididae	(dance flies)- streams & rivers, esp. in detritus; littoral zones of ponds & lakes; wet soil
Dolichopodidae	margins of ponds, lakes, rivers & streams; leaf-miners in aquatic macrophytes; marine intertidal; estuaries
Infraorder Cyclorrhapha
(Section Aschiza)
Superfamily Phoroidea
Phoridae	(humpback flies)- burrowers; predators on Psychodidae
Superfamily Syrphoidea
Syrphidae	(rattail maggots, flower flies)- pond & lake margins, esp. in fine particle detritus & on water plants; shallow marsh & bog pools; tree holes; polluted water
(Section Schizophora: Subsection Acalyptratae)
Superfamily Sciomyzoidea
Coelopidae	(seaweed flies)- breed in decaying seaweed around the high water mark
Dryomyzidae	moist places, including the seashore
Sciomyzidae	(marsh flies)- marshes; margins of streams, ponds & lakes, esp. near emergent macrophytes; temporary ponds; salt marshes; larvae predators or parasites of aquatic & terrestrial snails
Sepsidae	(black scavenger flies)- decaying organic matter; terminal drying phase of temporary pools; dung
Superfamily Heleomyzoidea
Sphaeroceridae	(small dung flies)- decaying organic matter; terminal drying phase of temporary ponds; dung; septic tanks; wet waste disposal sites
Superfamily Drosophiloidea
Ephydridae	(shore flies, brine flies)- littoral zones & margins of lotic & lentic habitats, often near or within stems of aquatic macrophytes; temporary waters; saline lakes & pools; salt marshes; marine intertidal; pools of crude petroleum; hot springs
Canaceidae	(beach flies)- on algae in intertidal zone
(Section Schizophora: Subsection Calyptratae)
Superfamily Muscoidea
Scathophagidae	(dung flies)- burrowers in tissues of aquatic macrophytes in lakes & ponds; in rotting seaweed; damp soil; sewage treatment beds
Anthomyiidae	(root maggot flies)- littoral zones of lakes & ponds, often those that have been enriched by organic wastes; tree holes; a few species in streams
Sarcophagidae	(flesh flies)- semiaquatic; burrowers in macrophytes

Feeding

The dietary diversity of aquatic dipteran larvae parallels the habitat diversity. Some families are shredders of coarse particulate detritus (Tipulidae); others are specialized for filter feeding (Simuliidae). Some families are specialized scrapers (Blephariceridae), consuming periphyton and associated materials from the surface of the substrate of fast-flowing streams. Other families are predaceous. Representatives of every functional feeding group have been reported among the aquatic dipterans.

Indicator value

Dipteran larvae occur in almost every conceivable aquatic habitat, from the bracts of pitcher plants (Culicidae: Wyeomyia), tree holes (e.g., Chironomidae and Culicidae), saturated soil, and mud puddles, to streams, ponds, large lakes, rivers, and even the marine rocky intertidal zone. Some 32 families of Diptera contain species whose larvae are either aquatic or semiaquatic. Aquatic dipterans represent some of the best known insect forms, including mosquitoes, black flies, midges, crane flies and horse flies, many of which are the most troublesome of all insect pests, particularly in terms of human health and economics. Despite this, many groups of aquatic Diptera play pivotal roles in the processing of food energy in aquatic environments and in supporting populations of fishes and waterfowl.

Some physiological and ecological tolerances and requirements of common dipteran larvae (Mackie, 2001)

Species	General habitat	Feeding	pH	Oxygen %	Trophic level
Family Deuterophlebiidae
Deuterophlebia spp.	clingers on rocks in mountain streams	scraper	<7 - >7	100	Oligo
Family Blephariceridae
Blepharicera spp.	clingers in streams	scraper	<7 - >7	100	Oligo
Family Tipulidae
Antocha saxicola	clingers in silk tubes in streams	scraper	>7	≅100	Oligo
Family Psychodidae
Psychoda alternata	burrowers in lakes, streams	gatherer	5.5 - approx. 7	50-100	Meso
Family Athericidae
Atherix variegata	erosional streams	piercer	6 - >7	≅100	lower Oligo
Family Syrphidae
Eristalis tenax	burrow in organic bottoms of streams, lakes	gatherer	<7 - >7	< 25	Eutro
Family Scathophagidae
Spaziphora spp.	sewage ponds	scraper	<7 - >7	<25	Eutro
Family Simuliidae
Simulium spp.	erosional streams or wave swept shore of lakes	filter feeder	<7 - >7	≅100	Oligo
Prosimulium spp.	erosional streams	filter feeder	<7 - >7	≅100	Oligo
Family Chironomidae
Ablabesmyia spp.	streams, lakes	piercer	<7 - >7	25-100	Eutro
Chironomus plumosus attenuatus, riparius	burrowers in tubes in streams, lakes	gatherer, shredder	<7 - >7	25-100	Eutro
Cricotopus exilis	on rocks in streams	piercer	>8	25-100	Eutro
Cricotopus bicinctus	streams, lakes	shredder	> 7	25-100	Eutro
Cryptochironomus fulvus	burrower, streams, lakes	piercer	<7 - >7	25-100	Eutro
Dicrotendipes spp.	burrowers, lakes, streams	gatherer, filter feeder, scraper	>7	25-100	Eutro
Polypedilum fallax	clinger, streams	shredder, gatherer, piercer	≥7	25-100	Eutro
Procladius culiciformis	streams, lakes	piercer		25-100	Eutro
Rheocricotopus robacki	erosional streams	gatherer, shredder, piercer	<7 - >7	25-100	Indifferent
Rheopelopia	erosional streams	piercer	<7 - >7	100	Oligo
Rheotanytarsus exiguus	in tube or net, fast streams	filter feeder	<7 - >7	<50	Eutro
Tanypus punctipennis	lakes	piercer	>7	25-100	Eutro

References and web URLs:

Hutchinson, G.E. 1993. A Treatise on Limnology. Vol. IV, The Zoobenthos. Ed. Y.H. Edmondson. John Wiley & Sons, Inc. Xx, 944pp.

Mackie, G.L. 2001. Applied Aquatic Ecosystem Concepts. Kendall/Hunt Publishing Company. xxv, 744 pp. ISBN 0-7872-7490-9

Narf, R. 1997. Midges, bugs, whirligigs and others: The distribution of insects in Lake "U-Name-It". Lakeline. N. Am. Lake Manage. Soc. 16-17, 57-62.

Peckarsky, B.L., P.R. Fraissinet, M.A. Penton, and D.J. Conklin, Jr. 1990. Freshwater Macroinvertebrates of Northeastern North America. Cornell Univ. Press. xii, 442pp.

Wetzel, R.G. 1983. Limnology. 2nd ed. Saunders College Publishing. Xii, 767pp, R81, I10.

Williams, D.D., and Feltmate, B.W. 1992. Aquatic Insects. CAB International. ISBN: 0-85198-782-6. xiii, 358p.

Mandaville, S.M. 1999. Bioassessment of Freshwaters Using Benthic Macroinvertebrates-A Primer. First Ed. Project E-1, Soil & Water Conservation Society of Metro Halifax. viii, Chapters I-XXVII, Appendices A-D. 244p.

For the entire Report, download all the files in the subdirectory, Primer1
Chapter XII: Order Diptera (two-winged or true flies)

Tree of Life

New York Department State of Environmental Conservation

"Sounds provided by and copyrighted to Naturesongs.com, 1997-2004"

We salute the Chebucto Community Net (CCN) of Halifax, Nova Scotia, Canada for hosting our web site, and we applaud its volunteers for their devotion in making `CCN' the best community net in the world