by Sarah Lloyd
Ovipositing fly of the Platystomatidae family
This fly (~8mm long) was photographed on a farming property south of Cressy. It belongs to the Platystomatidae family and is possibly a Rivellia sp. Members of this genus are similar in appearance to Lamprogaster species (see Wings page 76) but they have long transverse bands on their wings rather than the usually thicker, triangular shaped bands of Lamprogaster.
Adult flies are often seen on or near the dung of mammals on which they feed. But the biology of these flies – as with many invertebrates – is not well known.
The habitats of the larval stage of Platystomatids are varied. They occur in living and dead vegetable matter and in Europe have been found in graves. Some live in plant trunks damaged by other insects or fungi, or in the tunnels made in fallen logs by beetles. Rivellia species are almost cosmopolitan and some Rivellia larvae live in bacterial root nodules on leguminous plants, probably including Acacia species. Larvae of another platystomatid species Elassogaster linearis have been found consuming the eggs of a locust; they also live in decaying vegetables. Larvae of Lenophila species have been found in damaged trunks of Xanthorrhoea species and adults are commonly found on the foliage.
There do not appear to be any records of platystomatids ovipositing into grass stems. The grass may be the host for the larvae, but it also may be a safe place for the larvae to hatch before they move to their host. Many fly larvae actively seek out their hosts so the females only need to deposit eggs in the general area.
- Daley, E. (2007) Wings, an introduction to Tasmania's winged insects. Riffles Pty Ltd, Buckland
- On The Fly. The interactive Atlas and Key to Australian Fly Families. Australian Biological Resources Study.
- CSIRO (1970) Insects of Australia. CSIRO, Canberra.
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