Until recently my carniolans have never propolized anything inside the hive. I have had deep supers on top of deep brood boxes and the bees never moved up. A few days ago I found out that the bees actually wanted to move *down* and after putting supers below the brood boxes the bees drew out 2 full frames of comb in 3 days. Another thing that happened (coincidentally?) is that the inside of the brood box and a fair portion of the bottom super have been completely propolized. The whole season I have never had to use a hive tool to inspect frames or even remove a super (when the supers were on top of the brood box). Fall is definitely in the air but our days are still in the mid 90's so I don't know if the weather has stimulated the bees into doing this or if the sudden shift in usable space has prompted this behavior but I am truly puzzled by it. I'm not going to ask if this is normal behavior so much as what the heck is going on?!?!
For reference, the brood boxes went from almost no propolis anywhere to looking like someone dipped the box, frames and all, into a vat of resin... in about 5 days. I'm not sure if I need to add this but almost every hive has 1 frame of capped brood with no empty cells followed by 2 more frames full of brood in various stages of development. There is actually honey being put up in all the empty spaces now where i'm pretty sure stocks of pollen used to be. These are all first year hives and the nectar flow from the alfalfa fields near my apiary has been fairly constant since early summer.
I would really just like to know what, if anything, prompted the propolis frenzy.