I haven't even received this month's ABJ yet so I have no idea what McAfee wrote about winter bees. But I happen to have all three of Mattila and Otis's paper open on my computer right now so maybe I can comment on this. 

Just to clarify Randy's "caveat:" The papers never call the colonies "deficient" in pollen. I've pasted the quote where they explain their "pollen limited" colonies. There's a big different between claiming bees are "deficient" and stating the colonies have had their pollen supply "limited." 

Out of curiousity, do colonies produce winter bees in California? I know there are dearth periods but during those periods do colonies produce winter bees? The Mattila and Otis studies found supplementing in the fall did result in a boost in bees, but these bees weren't winter bees; they were the shorter lived summer bees. 

I certainly wouldn't take any research done in Canada and apply it to bees in California. There are lots of parts of the US where Canadian research is probably applicable but colonies deficient in pollen in a warm climate wouldn't be high on my list. In fact, it wouldn't be on my list of comparable places at all. 

From "Influence of Pollen Diet in Spring on Development of Honey Bee Colonies." 2006:

Pollen Limited before Wintering (All Three Years).

Colonies were fitted with OAC pollen traps during the
fall to reduce the amount of stored reserves available
to them throughout the winter and subsequent spring.
Traps were installed in late August and were removed
when pollen foraging ended for the year in October.
Pollen was removed from the traps every 2-3 d,
weighed, and then frozen fresh at-20
C for use in the
feeding treatments. From the first to last fall, an average
of 2.1 +/- 0.03, 6.2 +/- 0.35, and 2.0 +/- 0.64 kg of
pollen was collected per colony in each year. Pollen trapped
colonies had less pollen than control colonies
when stores in comb were compared on 3 October 2001
(80 +/- 35 versus 780 +/- 180 cm2 per colony, respectively;
F=14.7; df=1, 12; P<0.01) and 18 September
2003 (700+/-279 versus 1,720+/- 356cm2 per colony; F=
5.2; df = 1, 10; P =0.04).

From the same research project but published in a different article, "Manipulating pollen supply in honey bee colonies during the fall does not affect the performance of winter bees." 2007:

The traps were shown previously to reduce pollen stored in comb by 60%-89% in pollen-trapped colonies compared with control colonies.

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