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 Major Groups | Insecta (insects) | Diptera (true flies) | Chironomidae


Major Group: Insecta
Order: Diptera
Family: Chironomidae

Descriptive Features:

  • head capsule complete, directed forwards (prognathous), not retractile
  • mandibles usually with several teeth
  • abdomen 9-segmented 
  • abdominal segments scarcely longer than wide 
  • body smooth
  • spiracles usually absent but if present then head directed anteroventrally
  • anterior and posterior prolegs may be both present or both absent or only one pair present
  • anterior prolegs paired, fused or absent
  • posterior prolegs short or absent
  • Total length: up to 20mm
  • Taxonomic Checklist: Subfamilies

    Distribution: Australia wide

    Sensitivity Rating: SIGNAL grade 3-8. The more common subfamily Chironominae has a SIGNAL grade of 3 which is sometimes used for Chironomidae when subfamilies have not been discriminated. "Larval chironomid species track ecological conditions closely, and their distributions have long been used to assess water quality." (Bugledich 1999) 

    Functional Feeding Group: gathering & filtering collectors, predators, shredders, scrapers

    Ecology: As a family group, chironomid adults are commonly known as ‘non-biting midges’.
    Instream habitat: Chironomidae species can be collected in the whole range of habitats from the most pristine environments to the most polluted, stagnant to fast flowing lotic waters, freshwater to saline waters. Larvae are most commonly found amongst benthic debris and aquatic vegetation but also in pools on isolated granite outcrops, sandy substrates with overlying fine organic material, snag habitats, hygropetric seepages and muddy lake beds. Pupae may found in the water column near to the surface or attached to submerged substrata or amongst benthic debris.
    Feeding ecology:Most chironomid larvae are not restricted to a single feeding mode. Factors including larval size, maturity, food quality, sediment composition and seasonal or environmental change can influence their feeding behaviour. Gathering collectors feed on organic detritus deposited on submerged substrata. Filtering collectors feed on suspended diatoms and fine particulate detritus filtered from the water column using secreted silk nets. Scrapers use well-developed mandibles to scrape algae, bacteria and diatoms from the surface of rocks, sediments, wood and other submerged objects. Shredders use chewing and wood boring to feed on living macrophytes, submerged wood, macro-algae or leaf litter. Predators prey on other species of Chironomidae, oligochaetes, nematodes and various small invertebrates.
    Habit: Some Chironominae larvae contain the red blood pigment haemoglobin, which enables them to absorb oxygen from the water more readily; this has given rise to the common name of ‘bloodworms’. The true wood-mining species form excavated galleries in submerged wood. Mud-dwelling species usually build tubes of silt, sand-grains, vegetable matter or other benthic materials. These tubes may be gelatinous or silken tubes coated with particles of debris or attached to debris. Chironominae tend to be eurythermic (tolerating a wide range of temperatures). Orthocladiinae and Podonominae tend to cool stenothermy (tolerating only within a limited range of temperature).
    Life history: Duration of the chironomid lifecycle is variable. In temperate regions, many chironomid species are univoltine or bivoltine, but multivoltine species, with up to four generations in a year, are not uncommon. Species living in cold regions may take more than one year to complete their life cycles and tropical species may have life cycles as short as a few weeks. Females typically produce only a single batch of eggs which are either broadcast over the water surface or deposited in a gelatinous mass on emergent vegetation. Chironomid eggs hatch within a few days to one month. Larvae pass through four instars before pupating. The first larval instars may be planktonic and later instars are usually benthic. Towards the end of the fourth instar, the larval thoracic region begins to swell with the formation of the pupal integument and adult tissue. After ecdysis, the pupae usually remain hidden in debris or attached to the substratum until it swims or rises to the surface where adult emergence takes place. The pupal stage is short, lasting just a few hours up to several days. Adults often emerge simultaneously, in huge numbers, and form vast mating clouds, often at sundown and close to eutrophic water bodies. Emergence is usually short in duration, lasting no more than a month and intensive emergence can occur within a period of one to two weeks. Univoltine species emerge in early spring, late autumn and winter. Bivoltine species emerge in spring and summer to early autumn. Multivoltine species generally emerge between spring and autumn. Chironomid adults usually live only for a few days, although some species survive for a few weeks.

    live bloodworms on a snag



    Information Sources: Bugledich et al. 2007, Cranston 2000, Bugledich 1999, Colless & McAlpine 1991, Evenhius  2007, Berg 1995, Tokeshi 1995, Williams 1980, Hawking & Smith 1997, Gooderham & Tsyrlin  2002, Williams & Feltmate 1992, Merritt & Cummins 1996, Cranston & Hardwick 1996
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