There is an active population of these flies just outside my house among the leaf litter under a sapling Acacia tree. The tight association of these males with the numerous other flies in the immediate vicinity that are of similar size and behave in the same manner leads me to make the tentative assumption that these are the females of the same species (image below):



I find myself wondering why there are so many of these flies in one small area and what is keeping them so preoccupied for the better part of the day... From the information I have read, I suppose I could speculate that the females are investigating possible buried sphecid prey on which to lay their eggs, but then what are all the males doing? Any input regarding the feeding or mating behavior of these flies would be most welcomed!