Hello Dee and All, Dee wrote: > Now we all know that in the Natural that drones breed mites > and workers for the most part don't! All we have come to realize for sure is that varroa seems to prefer drone brood of all its hosts and turns quickly to mellifera worker brood if drone brood is not available BUT CERANA. . There are at least several possible reasons of which cell size is ONLY ONE OF THE POSSIBLE REASONS. (i.e. look at apis > cerana! Apis cerana is the odity of the bees varroa preys on. After doing a huge amount of research on cerana I have come to rule out the cerana cell size as the only factor why varroa DOES NOT reproduce in cerana worker cells. I could not find one case of varroa ever reproducing in a cerana worker cell. The material I read states VARROA DOES NOT REPRODUCE IN CERANA WORKER BROOD. All material I looked at seems to conclude the above as fact . Although cerana in certain parts of the world lives on a cell size similar to mellifera on the small size 4.7mm to 4.9mm varroa still does not reproduce I have read in worker cells. Most cerana worker cells are quite a bit smaller than 4.7mm in China and the drone size (I have read in the book Asian Apiculture) is around 4.7mm. Varroa has been found to be able to reproduce in worker cells of all mellifera AND simply moves to worker brood when drone brood is not available. Even scutellata and capensis. Capensis tolerates varroa best of all feral mellifera I have been told. Cerana and mellifera WILL NOT CROSS (Asian Apiculture book). In short cerana are similar bees but not exactly alike. Not being alike it is difficult to use cell size as the reason varroa does not reproduce in cerana worker brood as different juvenile growth hormones might come into play. I will be the first to admit I thought for quite awhile the reason varroa never reproduces in cerana worker brood was cell size and I posted several years ago I thought cell size was the reason. . After looking further, reading further and talking to cerana researchers I believe the reason not to be cell size but another yet unfound reason. All researchers I have talked to are quick to say we simply do not know why varroa does not reproduce in cerana worker brood. When pressed researchers seem to agree and three possible reasons. 1. different JGH than mellifera 2. shorter post capping time than mellifera in most instances 3. smaller cell size which cramps varroa reproduction. All of the above is from memory. If a knowledgeable cerana researcher on the list has better information please correct me if I am wrong in my analysis of cerana . I always want correct information in my posts and I am only a beekeeper and not a researcher. Sincerely, Bob Harrison