JWPalmer is correct. The entire southwest of the US has had Africanized bees for maybe 25 years. The bees are evolving to become less defensive and I'll give my opinion why that is.
The first question we need to ask is why the bees in Africa are so defensive and tend to swarm early. My opinion is predation. The hives are preyed upon by man and animals. The hives that were the most aggressive tended to survive compared to the hives that were more docile.
Swarming is similar. Because so many hives were destroyed, it was better to cast off a swarm before you were destroyed. In fact, if there was not so much predation the swarms would overpopulate the area and many would starve.
But when the bees were brought to the Americas, they encountered a different environment and they began evolving in response to that environment.
I’ll talk about my area because I’m most familiar with it. We have lots of wild bees inhabiting every kind of cavity. Some wind up in the walls of houses, some in block fence walls, some in cable TV boxes in the ground, large birdhouses, etc. If those bees are extremely defensive, and sting people who come close to them, they are usually exterminated. The bees that are docile and leave people alone are not noticed and survive.
The bees I keep are what I consider docile. I can walk in the area of the hives and the bees ignore me. When I open a hive, after smoking the hive, the bees do not “attack” me. They are flying around but don’t seem to come at me in any mass. And after I close the hive they do not follow me when I leave the hive area.
I can cut grass around the hives with a gasoline lawn mower and the bees ignore me. So all-in-all, they are docile enough for me and do not pose a threat to me, my animals, or anyone else.
You can get a hive that is defensive. Genetics being what they are, the defensive genes can appear in a mating and you can get a defensive hive. I consider a hive excessively defensive if the bees follow me after I’ve worked a hive and departed the hive area. I give them two chances, just in case they were upset one day. But if it happens twice, I exterminate the hive. [Added note: actually, there are other signs that a hive is defensive. When you open a defensive hive you can tell if you have experience with enough hives.]
The bees are productive. I don't keep records of how many pounds of honey each hive produces - I just do this for a hobby - but I get what I consider a lot of honey out of each hive.
I do not notice excessive swarming with the bees, and perhaps that has evolved also. Around here the problem for a swarm is finding a suitable cavity to set up housekeeping in. If the bees swarm excessively most swarms will fail.
The upper geographical limit for Africanized bees is not too far north of me. Seeley has noted that as you approach the northern limit the genetics change to a greater hybrid with the European bees. Maybe I'm in that zone.
I think we’re blessed with the local bees. Except for the risk of excessive defensiveness keeping bees here is very, very easy.
[One thing I'll add is that I'm a LOT less tolerant of defensive bees than when I first started beekeeping. I just thought that's the way bees were.]
