Moths of Toowoomba

ICHNEUMONIDAE Wasp

Hyposoter didymator ICHNEUMONIDAE

This is not a usual post for this Blog which is primarily about the moths of our property, but I feel it
may have an interesting connection to the reduction in the number of moths we have seen over the years. This cocoon was found in a reserve a little to the West of us in Toowoomba.

The black and white cocoon in the photo belongs to a Hyposoter didymator, which is a solitary wasp that parasitises the larvae of native Noctuid moths in the army worm, cutworm, cluster caterpillars and semi-looper families. Most of these moths are pests on various pasture grasses, crops, and pine seedlings in  Australia and Norfolk Island.

Deliberately introduced into Western Australia from Greece in 1983 and then introduced into Queensland and Victoria from Western Australia in 1991 to try and control the pest species mentioned.

They develop in the host larva for about 2 weeks, the larva eventually dies and the wasp emerges and
spins a silk cocoon where it pupates within 1–2 days. Females live for about 4-5 weeks after emergence, males only 2-3 weeks.

They were often bred in captivity and released in attempts at biological control of the pest species.
There are other parasitising wasp species in Australia.

The cocoon which is about 8-10mm in length is on a Warrior bush or Broom bush ( Apophyllum anomalum, CAPPARACEAE ), which is a common host plant for Caper white and Caper gull butterflies. It is therefore likely that the host larva in this case might have been a butterfly species instead of a moth species.

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