Wednesday, July 21, 2010

Perga dorsalis (Spitfires)

From Spitfire
PIRSA Forestry
Photos: M. Taylor

Another chance to talk about Kings Park Fauna!

These little fellows are called Spitfires because when disturbed, they emit a nasty looking yellow mucus from their mouths. They don't really spit; it's more of a drool. You can see some of this goo in the second photo below.

There are other species of crawlies that are called spitfires and some are true caterpillars that may have stinging cells on the ends of hairs that can cause a bit of pain. But not these gooey bugs; they can cause no harm to humans in either their larval or their adult phase and they are not caterpillars at all. They are wasp larvae.

From Spitfire
These guys have recently hatched, and once they have enough energy stored up they will pupate for up to 2 years before they emerge from their cocoons as Steel Blue Saw Flys.

P. dorsalis will always be seen in groups of individuals and they communicate by tapping their tail. You can tell from the first picture that they can do considerable damage to their host tree which is most often a Eucalyptus.

When the Perga dorsalis grows up it will become a wasp but it doesn't sting and it looks more like a large fly (like a horse fly.) I'll direct you to the Australian Insects website for pics of the adult wasp because I don't want to run afoul of any copyright issues and I didn't have time to wait for these fellows to grow up.

M. Taylor

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