Had something similar happen to me this afternoon.
After launching I hovered at around 200' while I adjusted some settings and set the focus. While sitting there a few curious bees came by to check out the MPP. As I flew away those few initial bees apparently went back to the hive and got all their buddies; suddenly there were a whole bunch swarming around. I ascended but they followed me up. I ascended again and flew forward and they seemed to give up at that point; I didn't see them again for the remainder of the flight. When I landed there was a bit of bug juice on the MPP's fuselage, so I think I puree'd a few of them.