01 September 2011

Tangle-veined Fly - Trichophthalma sp.

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Tangle-veined Fly - Trichophthalma sp.

The Tangle-veined Fly belongs to the Tabanoidea Superfamily that includes such nasties as the March and Horse Flies.  However in the Trichophthalma family Nemestrinidae, instead of feeding on blood, feed on flowers via a long sucking proboscis.  They are often seen hovering with rapid wing-beats whilst feeding, or will hover in the same spot for some time before darting away only to quickly return.  This activity and their solid build suggest a Bee Fly, but with those flies the wings are much longer and they don’t have an extended point to their abdomen.

Also like Bee Flies, Tangle-veined Flies are softly hairy, plus their larvae are parasitic on various insects including grasshoppers, so both play an important role regarding insect control.  The pointy end of the female abdomen contains a retractable ovipositor (for egg-laying) and is probably used to favourably place their eggs on or within an insect host.

The wing venation is quite congested compared to most fly wings, which is how they get their Tangle-veined common name.  Above, the fly is feeding from a common shrub of coastal calcareous sand, Logania vaginalis that is detailed in the Esperance Wildflower Blog (located top right).  These flies are not an evolutionary new-comer but have a long linage, as they also occur in South America to suggest a Gondwana origin.