Africanized Bees

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Africanized bees

The Africanized bee (Apis mellifera scutellata ), or "killer bee," is an extremely aggressive honeybee. This bee developed when African honeybees were brought to Brazil to mate with other bees to increase honey production. The imported bees were accidentally released and they have since spread northward, traveling at a rate of 300 mi (483 km) per year. The bees first appeared in the United States at the Texas-Mexico border in late 1990.

The bees get their "killer" title because of their vigorous defense of colonies or hives when disturbed. Aside from temperament, they are much like their counterparts now in the United States, which are European in lineage. Africanized bees are slightly smaller than their more passive cousins.

Honeybees are social insects and live and work together in colonies. When bees fly from plant to plant, they help pollinate flowers and crops. Africanized bees, however, seem to be more interested in reproducing than in honey production or pollination . For this reason they are constantly swarming and moving around, while domestic bees tend to stay in local, managed colonies. Because Africanized bees are also much more aggressive than domestic honey bees when their colonies are disturbed, they can be harmful to people who are allergic to bee stings.

More problematic than the threat to humans, however, is the impact the bees will have on fruit and vegetable industries in the southern parts of the United States. Many fruit and vegetable growers depend on honey bees for pollination, and in places where the Africanized bees have appeared, honey production has fallen by as much as 80%. Beekeepers in this country are experimenting with "re-queening" their colonies regularly to ensure that the colonies reproduce gentle offspring.

Another danger is the propensity of the Africanized bee to mate with honey bees of European lineage, a kind of "infiltration" of the gene pool of more domestic bees. Researchers from the U.S. Department of Agriculture (USDA) are watching for the results of this interbreeding, particularly for those bees that display European-style physiques and African behaviors, or vice versa.

When Africanized bees first appeared in southern Texas, researchers from the USDA's Honeybee Research Laboratory in Weslaco, Texas, destroyed the colony, estimated at 5,000 bees. Some of the members of the 3-lb (1.4 kg) colony were preserved in alcohol and others in freezers for future analysis. Researchers are also developing management techniques, including the annual introduction of young mated European queens into domestic hives, in an attempt to maintain gentle production stock and ensure honey production and pollination.

As of 2002, there were 140 counties in Texas, nine in New Mexico, nine in California, three in Nevada, and all of the 15 counties in Arizona in which Africanized bee colonies had been located. There have also been reported colonies in Puerto Rico and the Virgin Islands. Southern Nevada bees were almost 90% Africanized in June of 2001. Most of Texas has been labeled as a quarantine zone, and beekeepers are not able to move hives out of these boundaries. The largest colony found to date was in southern Phoenix, Arizona. The hive was almost 6 ft (1.8 m) long and held about 50,000 Africanized bees.

[Linda Rehkopf ]