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Australian Wildlife

  Sirex Wasp (Sirex noctilio)





Sirex Wasp | Sirex noctilio photo
female Sirex Wasp

Image by H. Dumas - Some rights reserved.    (view image details)

Sirex Wasp | Sirex noctilio photo
female Sirex Wasp

Image by H. Dumas - Some rights reserved.    (view image details)



SIREX WASP FACTS

Identification
Sirex Wasps are metallic blue with orange brown wings. Females have pointed abdomens and orange brown legs. Males have a broad orange band on the abdomens and dark brown legs. The female has a spike on the end of the abdomen to protect the ovipositor.

Size
length to 40mm long

Food
The Sirex Wasp is a serious pest in pine plantations in Australia. The females deposited a fungus into the trees when laying their eggs. This fungus grows as a food for the larvae, and weakens the host trees. after an attack, the crown of the tree wilts, turns yellow and then reddish brown. Beads of resin are seen on the trunk where the wasp wounded the tree to lay eggs. In severe cases, the whole tree dies. Sirex wasp is a particularly destructive boring insect pest in Pinus radiata plantations.

Breeding
The female wasp lays one to five eggs in the tree wood by drilling through the bark. The eggs are deposited with mucus containing fungal spores. The tree exudes beads of resin at the site of the damage. The eggs hatch into white larvae with a small spine at the end of their abdomen. The larvae bore into the wood and feed on the wood and introduced fungus. The larvae grow to about 30mm and pupate just under the bark. The adult wasps chew a round hole holes 3mm to 7mm in diameter in the bark to emerge one or two years after the egg was laid.



Classification
Class:Insecta
Order:Hymenoptera
Family:Siricidae
Genus:Sirex
Species:noctilio
Common Name:Sirex Wasp