The cross-breeding was accidental, when a queen bee escaped from an apiary in South America.
All bees release a pheromone when the stinger, stuck in the victim, is released and becomes airborne.
The killer bee's pheromone is stronger than domestic bees when torn from the abdomen, but the reaction to the venom is similar to domestic bees.
What differentiates killer bees from domestic bees is the ferocity and number of stings which create a severe reaction to the number of venom stings
which overwhelm the victims immune system.
I would like to see what these bees could do to an Asian Giant ‘Murder’ Hornet.............