I reached that conclusion a while back. I think its particularly difficult on virgins emerged in a bee free incubator. I think if you're going to emerge virgins they should emerge in a queen bank not an incubator. Use the incubator to day 14 and then place caged cells in the bank so that the virgins are attended to by the bees. There is no substitute for proper care and feeding of these new queens.This has made me think that it may be more important than I had considered to emerge the queen in a colony.
I am not sure what I think the losses are due to. I have reason to think it may be virgin introductions gone bad, possible weather, that 50% is the best we have seen so far from these compartments, or who knows what. I am thinking this may be one of those issues that is a while in answering. I wll see if introducing cells makes a difference in a few days.I've just introduced 20 virgins into nucs from mini's to 3 frames, from nurse bees to cell builders. As long as they are within 12-24 hours it's no fuss to directly release them. They are just a young emerged bee at that point. In years past I've introduced in cages and had them starve. I like to see 1/2 of the batch emerge in the incubator before making up allll the mating nucs that may or may not be needed. The other 1/2 go into the mating nucs as cells. Good luck with them.