Hi All On this thread it was mentioned that feral populations of AHB in some areas have shown some parasitism by varroa despite the fact that they should have smaller cells. I think the gist of things here is that africanisation results in progressively smaller cells over time. The first fronts of africanized bees have intermediate size ofspring and as time progresses the cell size eventually is supposed to stabilize at about 4.9. In much of the feral US population a high degree of europen geneflow into the african population could be expected due to frequent requeening. As a result many bees that are africanized are probably not completely africanized, and will have cells which are large enough that varroa can get a hold. (big cells = longer brood cycles = build up of varroa in worker cells) I would be interested to hear if anybody has found references to the use of 4.8mm cell sizes? This is the lowest limit known for A.mellifera.capensis I believe. (Approximately the size of certain of my bees) Keep well GArth --- Garth Cambray Camdini Apiaries 15 Park Road Apis melifera capensis Grahamstown 800mm annual precipitation 6139 Eastern Cape South Africa Phone 27-0461-311663 On holiday for a few months Rhodes University Which means: working with bees 15 hours a day! Interests: Fliis and bees Disclaimer: The views and opinions expressed in this post in no way reflect those of Rhodes University.