Prey Selection Methods

The males usually flew over the area and rested on the gound for only short periods. Prey was usually captured in flight; on only four occasions was a single male observed to attack potential prey from the ground. The flying males typically changed their direction if other insects crossed their flight path within a maximum distance of 2 m. They then captured the prey in mid-air using all six legs, killing them immediately or following a short struggle on the ground after falling together.
If another male approached the hunting male in the air, the latter flew close, but did not touch him. Both would fly parallel at a short distance for some seconds before flying off in different directions. In only one case were both males observed to touch, separating and after a short struggle.
The females foraged mainly from vegetation, seldom from the ground. They perched head upwards on stems of flowers and grasses in open areas, turning their heads to follow the flight of potential prey. When one was identified, they quickly turned their bodies and flew towards it. The females also captured their victim using all legs and either fell or flew to the ground with it. The predator then usually laid on its side, manipulated the victim skilfully with its legs and killed it by piercing the thorax. One female was observed to successfully complete 54 out of 63 darting capture flights. When the temperature increased, especially at midday, the flies flew with their prey into the vegetation to find shadow.
The behaviour of the females can be summarised as follows:

  1. Optical fixation by movement of the head.
  2. Alignment of the body towards the victim.
  3. Darting flight.
  4. Capturing in the air.
  5. Landing on ground.
  6. Manipulation with the legs.
  7. Killing by piercing.
  8. Transport of the victim (on some occasions).
  9. Sucking out and occasional manipulation.