What Bug Is That? The guide to Australian insect families.

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Dixidae

Overview

The Dixidae are a world-wide family of some 200 species. There has been little study of Australian Dixidae and life history information is needed to validate the current generic placements. Few larval associations have been made in Australia.

Adults do not feed and are found close to the aquatic natal site, resting in shaded places or forming swarms.

Dixid larvae feed by filtering fine particles from the surface film of standing or slowly flowing water bodies, using sweeping movements of the labral brushes. They will move into the hygropetric (madicolous) zone, crawling in their 'U'-shape in surface films of rocks. Dixid eggs are laid in masses at the edge of water bodies.

Description

Adult Dixidae are slightly built, resembling delicate mosquitoes (Culicidae, to which they are related) but with a short proboscis, short-haired antenna, scale-less wings, and with a  characteristically curved stem of wing vein R2+3. Larval Dixidae are easily recognisable in life by their 'U'-shaped posture on the surface film of standing and marginal flowing waters, hence the vernacular name of 'meniscus midges'. When preserved, the larvae have a strong resemblance to some mosquitoes, but they are easily differentiated by the circlets of hairs on several dorsal abdominal segments.

Distribution

Worldwide, excepting Antarctica. Four Australian species are allocated to Dixella Dyar & Shannon and two to Nothodixa Edwards. The latter genus is Gondwanan in distribution, and the former also has a preponderance of austral taxa. An undetermined fossil Dixidae has been recorded from the Lower Cretaceous Koonwarra Formation in southern Australia.

  • Dixidae larvae

  • Dixidae

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