Killer bees or Africanized bees are very aggressive! Other than their super defensive tendency, the African bees have only a few other characteristics that differ from ordinary, European honey bees. They are slightly darker and smaller than those of European bees. There are also some slight differences in certain body parts, such as the veins in the wings, which can be measured. These characteristics, however, cannot be distinguished easily with the naked eye. Even an expert looking at a European bee and an Africanized bee sitting on the same leaf could have trouble telling which is which. Researchers have developed measurement tests that can be used in the field for a preliminary identification but more extensive tests are generally required for a positive identification.
One possible reason for the success of Africanized bees in displacing milder-tempered bees is that in every respect, the Africans appear to be more efficient and more diligent. They get up earlier, work later and visit more flowers per foraging flight than do European bees. When the moon is bright, Africanized bees will often continue to forage late into the night. This workaholic attitude even extends to reproduction. Africanized queen bees lay eggs at a slightly faster rate than do their European counterparts. Colonies of African and Africanized bees also produce a significantly larger number of drones than do those of European bees.
Africanized bees are nervous in behavior. They tend to swarm more often and they are also more likely to abscond. “Swarming” occurs when part of the colony breaks off with the queen and flies off looking for another place to call home. The bees engorge themselves on their honey reserves before leaving so as to have sufficient energy to make it to a new location. There can be multiple swarms from one hive, since new queens can also emerge and fly off with part of the colony. When bees “abscond,” they all take off to find a new nest. Bees typically abscond when they sense a threat to their colony or when they detect signs that foraging opportunities have almost been exhausted in the present location. Africanized bees are more sensitive to threats than are other bees and they have also been selected over centuries to survive in areas where scarcity of resources is common and absconding is the only alternative if the colony is to survive. The tendency of Africanized bees to leave home at a moments notice makes them more difficult to manage and can limit the amount of honey that can be harvested from their hives.