Sand wasps are generally not aggressive toward humans – but don’t disturb their nests! They are solitary nesters but sometimes it is not unusual to find a number of nests in the one area. They dig a nest hole in the ground, often on the side of a sandy-gravelly walking track. The adults feed on nectar and are often encountered in a native garden.
After laying their eggs and the larvae hatch, the adult wasps prey on other insects, particularly flies, which they capture on the wing and immobilize with a venom and carry to the nest.
It is thought that sometimes the adults work in pairs, one catching the prey, the other guarding the nest burrow from predators.
Once the larvae are fed, the adult (female) exits the nest and fills the entrance in with sand to hide it from predators. When she returns with the next meal, she has to dig the burrow open again.
Bembix palmata (I think) belong to a genera of about 20 species.
I came across this wasp recently at the Frankston Conservation Reserve.