The killer bee is the Africanized honey bee. They are a hybrid of the Western honey bee species, produced by cross-breading of the African honey bee with various European honey bees. They are more defensive than any of the various European subspecies. Small swarms of of Africanized honey bees are capable of taking over European honey bee hives by invading it and establishing their own queen after killing the European queen bee. They produce more honey than European honey bees, but they attack more.
The proper name for the "killer bee" is the Africanized honeybee. Africanized honeybees are a hybrid that originated in Brazil following the importation of African honeybees in 1956. Beekeepers brought the African honeybees to South America, thinking that those bees would be well suited to honey production in the tropics. Instead, the African bees mated with the resident European honeybees, creating the hybrid (the offspring of genetically different varieties or species) Africanized honeybee.
Although they produce more honey than European honeybees, Africanized honeybees are problematic because they attack in great numbers. Since their introduction, Africanized honeybees have been responsible for approximately 1,000 human deaths.
Concern is now growing regarding the migration of Africanized honeybees into the United States. In October 1990, the bees crossed the Mexican border into the United States. They reached Arizona in 1993 and are expected to colonize other parts of the southern United States, probably by the year 2000. The killer bees will be restricted to the South because they cannot withstand colder climates.
Experts have suggested two possible ways of limiting the spread of the Africanized honeybees. The first is drone-flooding, a process by which large numbers of European drones (male bees) are kept in areas where commercially reared European queen bees mate. This will minimize the mating that occurs between Africanized drones and European queens.
The second method is frequent requeening, in which a beekeeper replaces a colony's queen with one of his or her own choosing. The beekeeper can then be assured that the queens are European, not Africanized, and that they have already mated with European drones.
Sources: Audubon Magazine, vol. 93, no. 2 (March 1991), pp. 14, 16; Flakus, Greg. Living with Killer Bees, pp. 7-8, 50; Scientific American, vol. 269 (December 1993), pp. 84-90.