Africanized (killer) Bees

All honey bees in southern Arizona are considered Africanized.

Yeah, that's why I pay close attention to how the bees act when I'm out and about. If I get bumped more than two or three times, I change course.

In the Midwest, at least in more forested parts of the Midwest, native bees are doing pretty well. Honeybees are being stressed by mites, hive collapse syndrome, and sensitivity to neonicitinoid insecticides. Honey bees are not native to America, they were introduced. When European bees were crossed with African bees, the result was a more robust hybrid but the undesirable trait for aggression was part of the bargain. That is part of the incentive to incorporate one gene at a time artificially rather than play craps with the entire genome. The old fashioned way of modifying genetics always included undesirable genes along with the desirable ones.

They are related to European honeybees and interbreed. They pollinate the same plants and are not visually distinct. Fortunately, they are not good at overwintering and only can survive in places with mild or non-existent winters because they don't build up sufficient stores to successfully survive a cold winter. For example, here in NJ, a managed colony needs about 60 lbs of honey to survive a winter. Africanized bees tend to use smaller cavities as hives that fill up and lead to swarming before large stores of honey can be generated.

European honeybees are considered gentle and are defensive only; they won't sting unless provoked, and moving away from the hive by 10-15 feet will usually end pursuit. Africanized are similar except they are more easily provoked by proximity (both in terms of distance and response) and will follow for much longer distances. This combination is what yields so many stings, because when a bee stings, it releases a chemical that increases defensive behavior in bees and makes them target the stung area (it smells like bananas). One sting is like painting a bulls eye on you for the bees and a hefty defensive response with following behavior from Africanized bees can generate a lot of stings, especially in the case of people/animals who aren't able to move away as quickly: the elderly, children, pets.

My wife and I recently took up bee-keeping.

One thing we've learned (not by first-hand experience, thankfully) is that domestic bees bred in Texas are are likely to have at least some minimal amount of hybridizing with the Africanized bees. These bees are not "killer bees," so to speak, but they are more aggressive than "standard" honey bees bred in other parts of the country. We know a couple bee keepers who have abandoned colonies because it was just too much of a hassle (and too difficult on pets, visitors, etc) dealing with their more aggressive behavior.

Standard Italian honey bees are not very aggressive at all--even as beginners learning the craft, we've been stung only a few times. I think one of our dogs got stung once when we first established the hive and he didn't know any better. But no one would ever be stung just because the bees happened to be out and about on the property, which does happen when colonies have the "meaner" hybridized bees.