About a hundred medium-size ants, looked like meat ants, clustered on stems of small black wattle, but could not see any other insects with them. Hairstreak butterflies and pupae were sighted in this wattle last summer (sighting 22 Jan) but I could not see any signs of them.
Hi Jacky, you are very likely right that they are meat ants (Iridomyrmex purpureus) but there is not quite enough detail in the photo to be sure. Cheers, Jon