Researchers say that the breed of so-called "africanized" honeybees sometimes known as “killer bees” for their protective, sometimes lethal instinct to attack when their hive is threatened have been detected in the Bay Area for the first time.

The Chronicle reports that UC San Diego researchers who have been tracking their movements say they discovered the bees in a Lafayette subdivision called Reliez Valley near Briones Regional Park. It's possible that the Bay Area's warming temperatures have led to the bees within our boundaries, but San Francisco's cooler temperatures likely insulate the city proper from any infiltration.

"There is most likely more than one colony," said Joshua Kohn, a UC San Diego professor of biology at UC San Diego. Still, there isn't necessarily cause for concern. “An Africanized honeybee out foraging on flowers is no more aggressive than your average European honeybee. Nor is the sting of an individual any different,” said Kohn. “It’s only when a hive is disturbed that the level of aggression from Africanized bees is elevated.”

It's unclear how the bees arrived in the first place — “There are so many ways the bees could be moved here" said Steve Schutz, an entomologist for the Contra Costa Mosquito & Vector Control District. But, he continued, "[it] doesn’t seem to have had an impact so far."

If you do see a large group of bees, says Kohn, you'll "probably want to have a professional beekeeper come deal with it.

The most recent and proximate death by killer bees occurred in Riverside earlier this month. There, a construction worker was killed when he and coworkers disturbed an underground hive, as the Daily News reported.

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