This is a follow up to a previous thread, now that I am sure of the identification of the insects concerned.
Over a period of three days about a dozen male Scolia flavifrons were observed around the same patch of vegetation flying continuously and fast with rapid changes of direction. The following images are sequential frames from a video at 25 fps.
The insects are about 3cm long so you can judge how rapidly this one was manoeuvring.
On the fourth day there was just one which suddenly landed on a tree leaf and allowed me to get a good still photo.
They then disappeared. All the insects were male (black faces). On the first day I was pretty sure I'd seen one (which had flown high with the sky as a background) chase and catch a small insect about the size of a midge. It seems clear that the behaviour would be consistent with these insects hunting other flying insects but this is not mentioned anywhere - they are described as living off flower nectar. If they were not hunting insects, what else could explain this behaviour?
Interesting behaviour. I can't imagine why the Scolia would be chasing insects, as they are nectar feeders, but probably part of courting behaviour, to attract or impress a female. Male wasps in my garden seem to hang around on a particular tree, occasionally taking flight, probably hoping to spot a female.
I had also come to the conclusion that it was to do with mating. Interestingly, they appeared again this year at exactly the same spot for about 3 days then disappeared. Hope they found what they were looking for.