How the Africanized bee defends differently than the honey bee
Africanized bees perceive the world differently than the typical honey bee. When any bee is feeling threatened it will sting you to defend itself. The stinger is left in your body and will pump the venom into your flesh, and pheromones into the air. The pheromones tell the bees around you that one of their own has perceived a threat and attacked. Depending on the proximity, the other bees may release the pheromones of their own. The pheromones will send nearby defensive bees out to sting, and continue to release more pheromones as a defense.
When the pheromone smell becomes weak, the regular honey bee will perceive that the threat is no longer a problem and will return to work. The Africanized bee, because of genetics, will continue to follow the threat for longer distances, and will be over stimulated by the scent, becoming angry, and much more aggressive. Both bees follow the same pattern of behavior; however the Africanized bees will continue to pursue the threat and continue to sting, instead of defending the hive and returning to work when the threat has left.