The swarming isn't what I wanted, and I couldn't get quite what I wanted..
The bees have a min/max velocity and try to stay near the hive. If they are far and facing away, they slow down, and if facing toward, they speed up. They can "turn" only so much per physics frame, and the turning rate is less when they're going fast... Also, they have a small collision area, and can bounce off of each other.