Chalcidoidea (superfamily)

1 A gall wasp or Chalcid wasp at Greenway, ACT

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Identification history

Chalcidoidea (superfamily)	19 Oct 2018	MichaelMulvaney
Chalcidoidea (superfamily)	13 Oct 2018	RogerF
Unidentified	13 Aug 2018	MichaelBedingfield

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User's notes

Among boulders on the east side of the Murrumbidgee River, south of Pine Island.

9 comments

MichaelBedingfield wrote:

13 Aug 2018

Rainer R. thinks that these unusual objects that look like woody fruits are caused either by insect galls or a virus from sucking insects. Is it possible to name the culprit?

RogerF wrote:

14 Aug 2018

You would need a sample to dissect and some to keep to see if anything emerges.. In other plants similarly shaped galls are sometimes induced by eriococcid scales.

MichaelBedingfield wrote:

14 Aug 2018

It is difficult terrain consisting mostly of large boulders and it will be hard to find the plant again, so I was hoping not to go back. But I will do so to collect samples when I get a chance.

MichaelBedingfield wrote:

24 Aug 2018

Hi Roger
The plant wasn't as hard to find as I expected. I was visiting the area with Margaret Ning to look at some Grevilleas and Rainer Rehwinkel was accompanying her unexpectedly. I took the opportunity to show him the plant. He assured me the unusual growths were galls. I took some home for closer examination. Most of the galls had a single hole indicating that the insect had left. The holes were tiny, about 0.5mm in diameter. I dissected one with a hole and there was an empty cavity in the interior. There were only 2 galls that didn't have an exit hole. The inhabitants may be dead.
So my question is what should I do with the specimens, especially the ones which may still have an insect inside?

KimPullen wrote:

16 Sep 2018

I'm interested to know the culprit too. You could put some galls into a bag and check it frequently to see what emerges. A ventilated bag (e.g. cotton or very fine mesh) is less likely to cause mould to grow on the galls, and you can spray them with water now and then to keep them fresh.

MichaelBedingfield wrote:

16 Sep 2018

Still waiting for something to emerge. Thanks for the advice Kim.

MichaelBedingfield wrote:

13 Oct 2018

It has been a long time since I collected the material. Nothing has emerged from the remaining galls and they were quite dry and hard. So I dissected them. All of them had an empty hollow inside but with no sign of life, except for one which had what looked like insect excreta but no insect.
So all the galls were duds.
I will need some assistance to find out what these insects are. I'm speculating now, but it seems that the important thing is to know when to harvest the material so that the insect inside the galls is mature enough to survive the challenge of a branch containing the gall being removed and then be able to emerge as an adult.

RogerF wrote:

13 Oct 2018

Sorry I missed your comment of 24 August. The small exit holes suggest the galls were induced by a species of gall-wasp. Hymenoptera: Chalcidoidea orCynipoidea. There are several families of gall wasps that induce such bud galls, notably Torymyidae (Chalcid). They mostly have annual life-cycles with the galls developing during spring and summer, so the best time to collect mature galls would be in autumn. Woody galls may persist for several years after the wasps have emerged. Its a different matter to identify the wasps as there are many species and expertise is no longer available. There are collections of galls and their inducers in ANIC. Another issue is that the primary gall inducers are often parasitised by other wasps notably from the family Pteromalidae, so what emerges may be a parsitoid or hyperparasitoid.
Have you tried looking through Bowerbird.

MichaelBedingfield wrote:

13 Oct 2018

I haven't done a search, but I put this sighting on BowerBird, including the Australian Wasps project, but I have got no ID response.

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