Hi Roger, I also think that some kind of learning process is involved. The bees seem to get better at cleaning the mites with time. And then don't have much of a problem with them after that. Do you have any new insights from your small cell bees? Regards Dennis :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::