Hi Dick, Sorry to hear about your top bar and small cell hive experiment. It sounds like it would be a great time to treat them with some oxalic. Get them through the winter and see what they do next season. I've found that it takes about a full season for bees to get into 'equilibrium' with the mites when on natural or small cell sized comb. Others have noted this also and have attributed it to a 'hive knowledge' or learning. It's a curious phenomenia which often requires hives to be treated the first year when on small cell. I think mite immigration is a big factor in the process. Bees on small cell comb behave very much like those on large cell throughout most of the summer. Mite populations can increase when a new small cell hive is started after most of the early spring broodnest cleansing is over with. When the bees have a chance to clean brood in the fall and continue to reduce the mite load over the winter, a different situation will exist the following spring. The hives will have an extremely low mite level which they can maintain inspite of mite immigration. I think that's how they 'learn' to control the mites. Regarding natural comb in a tbh. I've think that cavity shape has a profound influence on the amount of natural small cell comb drawout by the bees. A cavity that is too short will result in comb that is truncated before much small cell comb is drawn out. And typical top bar hive management often interfers with broodnest construction, resulting in lots of drone and storage inside the core area. I had problems with mites in top bar hives that I've managed in a traditional way. Treat them and let everyone know what happens next season. Regards Dennis -- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---