Major Group: Insecta
Order: Diptera
Family: Dixidae |
Descriptive Features: head capsule complete, not retractile into thorax
mandibles usually with several teeth
abdomen 9-segmented
paired prolegs only on 1st and 2nd abdominal segments
posterior abdomen bearing lateral, frequently setose, lobes on each side of a conical anal process
Total length: up to 6mm |
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Dixidae |
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Taxonomic Checklist: Species (both genera were formerly known as Dixa in Australia)
Dixella humeralis Tonnoir
Dixella nicholsoni Tonnoir
Dixella tasmaniensis Tonnoir
Dixella unipunctata Tonnoir
Nothodixa flavicollis Tonnoir
Nothodixa geniculata Tonnoir |
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Distribution: Australia wide
Sensitivity Rating: SIGNAL grade 7
Functional Feeding Group: filtering collectors |
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Mt Wills Creek near Dartmouth, Vic |
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Ecology: Instream habitat: Commonly known as ‘meniscus midges’, dixid larvae are usually found in fresh, still or slowly flowing waters such as dams, ponds, lake edges and stream backwaters. They live in the meniscus that forms the interface between the water and leaves of macrophytes, overhanging riparian vegetation, or flotsam accumulations, but also in the water surface film itself. Pupae are usually found above the water level on a rock or piece of emergent vegetation. Adults remain close to larval habitats.
Feeding ecology: Dixid larvae feed by filtering fine particles and planktonic algae from the surface film and just beneath the water surface, using sweeping movements of the brush-like mouthparts. Adult midges do not feed.
Habit: Larvae hang in the water surface film curled in a ‘U-shape’ and can swim with a jerky motion. When threatened, they dive under the water to resurface later. Pupae can swim. Adults may rest in shaded places or form swarms close to larval habitats.
Life history: Females lay eggs in masses at the edge of water bodies. Pupation can occur in water but typically takes place in damp earth or above the water surface on adjacent plants. |
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Information Sources: Bugledich 1999, Colless & McAlpine 1991, Hawking & Smith 1997, Williams1980, Evenhius 2007, Gooderham & Tsyrlin 2002, Ferrington et al. 2003
Key to Genera: none
Key to Species: none |
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