My understanding of pollen collection is that a colony of bees tries to maintain a critical mass of pollen, unlike honey hoarding. With honey, they will store many times the amount that they might "need" as insurance against future famine. A colony could live quite a while on honey alone, and perhaps ride out long winters or extended drought.

Pollen, on the other hand, tends to lose value over time so it appears that the wisdom of the hive guides them to stop hoarding pollen after they reach about a kilo of stored pollen. Now, the effort to maintain this quantity will result in a certain level of pollen foraging, which is in turn affected by the consumption of pollen. 

We don't know how quickly the colony will respond to the various factors: availability, quantity stored, consumption rate, etc. In fact, we don't even know how they evaluate these factors. But, it is likely that if the colony is building up very fast and there is a lot of pollen available, then there could be an immense flow of pollen coming into the hive at that period.

Then, if brood rearing is slowed for some reason, then the lack of immediate reduction in foraging could create an excess of pollen in a very short time. This excess would remain in place until pollen consumption exceeded pollen coming in, which may take a while to occur. 

I always thought that an excess of pollen was a good thing. It's usually found in the bottom box, especially if supers are added liberally throughout the season. I don't recall a time when I did not see this, but I kept bees for 16 years in San Diego County, which is the garden of eden for pollen collection. This was prior to varroa, so I doubt varroa is the cause.

PLB

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm