In an effort to improve honey production in the tropics, a scientist began some breeding experiments using some of the common European honey bees and crossing them with the A. mellifera scutellata bees. This Africanized mixture proved to have the highly defensive behavior of the African race. In 1957 some of the bees escaped, and they have been slowly spreading northwards ever since. Africanized honey bees reached Arizona in 1993. More than 211,000 beekeepers maintain about 3.2 million honey bee colonies in the United States.
Beekeepers often use their bees for pollination of crops rather than for honey production.
In fact, one third of our food production is the direct result of pollination by insects. So, although we will have to be more cautious of honey bees in the future, they will remain an important part of our environment.