I decided to try a polystyrene hive this year (BeeMax) and put the hive top feeder on after installing a package (4/4/12). Went out to do an inspection today and my girls have built a lot of comb on the bottom of the feeder. Nice comb...with pollen and nectar in the cells. They have drawn out 5 frames of plastic foundation, but I swear they like building on the styrofoam even more. I am too new at this to know if this is a problem. My bees in the wooden-ware get baggie feeders and there is no "mis-placed" comb.