Re: Africanized Bees - Are they really that bad?
In the 2004 study, the researchers found that when laying drone eggs, the hybrid AHB/EHB were more inclined to lay AHB drones/queens even when the queens were AI'd with equal amounds of AHB/EHB semen. They had no logical reason for this, but rather just noted the anomaly.
I think the most likely reason (conclusory allegation) for random appearances of AHB in northern states would be from queens raised or bred in any area where AHB drones might be present, and then any resulting supercedure could result in AHB queens.
Also, another consideration is, that suppose you have a queen that has been bred to a AHB drone, then that colony, which would cluster, could preserve the AHB genetic to overwinter, and then produce AHB queens the next fall. Another conclusory allegation, based upon logic only. However, I don't think (conclusory allegation), AHB would ever become 'established' as the predominant genetic bee line in an area where the winters require clustering for survival.
With regard to the rain barrier, please read my observation in my post #56, 1st paragraph.
"I only regret that I have but one life to lose for my country." Nathan Hale, 1776