I’ve got one of those big end of the season flies buzzing around inside my house. I would think the kitchen and the half full trash can would provide him with far more entertainment than me , but no, he continues to buzz my head and tries to get close to me at the other end of the house.
I shave and shower and don’t think I smell like a good bet for fly (vs the trash can) , but still he persists. I will eventually get annoyed enough to stalk and kill him, but am letting him alone for now as my back is giving me trouble.
I don’t know the answer to your question, but I do know that when I have flies buzzing around in the kitchen, and I go get the flyswatter out so I can smack them, they will all mysteriously disappear. So maybe get the flyswatter and keep it nearby and they won’t bother you.
Because we are warm and are a source of protein, which they require to breed. They are like flying vacuum cleaners and can only suck up stuff off our skin or from our tears to help them along.
I suspect the flies that follow people indoors are different from the flies buzzing around the garbage. Every fly that I’ve squashed indoors has had… Go squash one and see for yourself, but make sure you have a strong stomach first.
I don’t know about in-house flies, but I’ve gotten the vague impression that outdoor flies, encountered on the hiking trails, seem to be territorial. (Maybe even protecting their territory?)
What I’ve noticed is that a big horsefly-like critter will harass me by buzzing around, and following me along the trail for a ways. But after following me for a short way, they will leave (or maybe stay behind). I’ve gotten the impression that they stay within a short distance of their “home territory” and will be less likely to continue chasing you once you leave their turf.
The above is all just a rather vague impression I’ve often gotten from the behavior of flies in the wild. I don’t know if it would apply to your typical indoor domesticated pet houseflies.
On my jogging route is a field covered in cow pats with clouds of flies above them. As I run through, all of the flies chase after me, to the point where I will have a vast cloud of, certainly hundreds, possibly thousands, of flies chasing me. If I let them catch me they just buzz around me and don’t really do anything.
Evidently I must smell more like shit than a cow shit.