Note the long, distinctive yellow and black-banded legs characteristic of this species. Double-click to enlarge.
Stilt-legged flies (Rainieria antennaepes) are ichneumonid wasp mimics who walk with their front legs extended, appearing like wasp antennae. I have to admit that this fly did an excellent job of initially fooling me.
The adults feed on detritus and dung. The natural history of this species is poorly understood.
There has been an abundance of these flies around the peony bushes and along the green house siding.
Stilt-legged flies (Rainieria antennaepes) exhibiting its characteristic body posture and extended front legs. Double-click image to magnify.
Great photos Dave, especially the second one nicely displaying the leg-waving behaviour! One minor note; Rainieria adults aren’t predacious (at least that I’m aware of) instead generally feeding on detritus and dung. Another common North American genus, Compsobata, are predators however, and will take down smaller insects on foliage.
Corrected. Thanks, Morgan!
[...] It must be nearly summer, the stilt-legged flies are out and about again! Nice pictures of Rainieria antennaepes by Dave Stone at Things Biological. [...]
Although these flies are not predatory, they are still aggressive.
I have seen one of them defending it’s territory by grabbing intruder ants with it’s mouthparts or front legs and throwing them off the plant.