Like the fins on a cuttlefish. And if this fin is translucent and only catches the light depending on the light source and the angle of the body to the camera, then this fin will be illuminated along different parts of the body. The fin undulates along the body in varying patterns depending on what the maneuver the Rod is currently performing. Please remember, at these shutter settings, bugs still are identifiable as bugs. Bugs have shorter, more distinct bodies and legs hanging down.
Bugs have wings attached to the top of their body.
Their wings don't blur along the side of their body. All clearly evident at these higher shutter settings. As a UFO investigator and being well versed in the physical sciences, I'm now even more convinced of my assumptions regarding these Rods. Broadcast quality video that can demonstrate that the Rods are a unique phenomenon. They were taken by Mark Lichtle while filming parachutists jumping into a vertical cavern in Mexico, Sotano De Las Golondrinas-The Cave of the Swallows.