We’ve had a resurgence in European Wasps around home so I bought some traps, it’s not only wasps that come to the trap flies have also decided it’s a lovely place to visit. I noticed one fly seemed to be always sitting near the top so went to investigate. I watched and when another fly came near the big one would chase it away. I decided it might not be a big bully chasing away any other fly coming to sample the wares it might actually be a protector of the genus keeping the others away from danger!
You can see the captions if you hover the cursor over an image. Is my imagination in overdrive?
There was another visitor that gave me a laugh, a tiny spider that ran from place to place trying to catch one of the flies caught inside the trap. (Obviously caught when the big fly was off duty.)