Along the Mississippi River swarms of emerging mayflies have been seen on radar. The radar and image below are from a July 11, 2017 emergence near LaCrosse, Wisconsin. On the radar you can see the mayflies emerge from the river and head toward the north.
This image was taken in LaCrosse during the emergence.
Radar & Image Source: National Weather Service
Is it possible that other swarms have or can be tracked by weather radar?