“As an area becomes colonized, the Africanized bees will show their true colors—they will exhibit their intense defensive behavior,” said Mussen, a Extension apiculturist since 1976 and a worldwide authority on honey bees.

Beekeepers who collect swarms in colonized counties have a “high probability” of hiving an Africanized honey bee colony, he pointed out, and should always look for unacceptable defensive behavior.

“Massive stinging events involving Africanized honey bee (AFB) colonies have not been very numerous in the United States,” Mussen wrote in Bee Briefs, one of his two bee publications on the UC Davis Department of Entomology website. “Some of the worst incidents have involved dogs that have remained near the nesting site once the stinging commenced and received in excess of 2000 stings. In most human-stinging incidents, sting numbers have approached the hundreds at worst, but usually were less than one hundred.”

Modesto is only 68 miles from the state capital of Sacramento, but Mussen said area residents should not be worried. “They’re not moving north that fast,” Mussen said. It took the Africanized bees 37 years to reach California.

However, some individuals are highly sensitive to honey bee venom proteins and are subject to anaphylactic shock (allergic response) and can die from only one sting.  Senior citizens with compromised cardio-pulmonary systems seem to be at a higher risk for bee sting-induced heart attacks, Mussen said. On the other hand, beekeepers who have been stung many times develop protective antibodies and can tolerate more stings than non-beekeepers.

Mussen recommends that anyone working or relaxing in areas known to be colonized by Africanized bees “take precautions” by avoiding nesting areas. If the bees or wasps start to sting, cover your face with a shirt as you run for a building, vehicle or other shelter, he said. You can also carry an Army surplus gnat/mosquito veil with you to protect your face.

“Jumping into water will not help,” Mussen said. “Africanized honey bees fly around and will sting when you come up to breathe.”

The honey bees’ pheromone, resembling the scent of a banana, sounds the alarm, alerting other bees to attack.

“Africanized honey bees are not something to be feared,” Mussen said, “but they are to be respected.”