Killer bees prompt response by Alabama officials as invasive swarms spotted across U.S.

Beekeepers in southeastern Alabama recently trapped a "feral swarm" of killer bees,  according to the Alabama Department of Agriculture and Industries, the latest in a recent string of killer bee sightings across the U.S.

Officials said the swarm was humanely euthanized to protect the state's honeybee populations, which, University of Georgia researchers note, can be threatened by this more aggressive bee subspecies.

Killer bees, also called Africanized honeybees, are a notoriously dangerous breed known for their defensiveness, according to the Smithsonian Institution. Unlike most bees typically seen in the U.S., which are technically European honeybees, these killer bees became feared after attacking humans and animals in relatively large numbers. The Smithsonian writes in a description of killer bees on its website that the insects "have killed some 1,000 humans" since their introduction to the Americas in 1956, "with victims receiving ten times as many stings than from the European strain."