These small bugs bob up and down in the air. When Trace gets close, they dive down at him inflicting 200 damage if they collide. Being a small target, a small swarm can easily decimate Trace's health. They are not blocked by solid terrain, flying about freely in the background.
When corrupted, they take on the behaviour and characteristics of the Red Wasp, behaving much like their original form, but causing a lot less damage on contact.