Pete, I'm not seeing that the two studies are related. "Winter" bees are
typically reared from well-fed larvae, reared on fall pollen flows.  As far
as I can tell, they have very different physiology than those of the
nutritionally-stressed bees in the Wang papers.

* * *

Dr. Grozinger wrote to me and said, in part:

> We developed a model predicting that reduced environmental nutritional resources lead to altered pheromonal signaling in the colony, which leads to the production of winter bees (or long-lived bees during wet or dry seasons in tropical climates).  

From the paper she to which she refers:

Changes in availability of nutritional resources can shift
the timing of the entry to and exit from the overwintering
state. Increasing pollen stores through supplementary
feeding or restricting pollen stores by placing pollen traps
across the colony entrances will, respectively, delay or
accelerate the timing of the production of long-lived
winter bees relative to control colonies *

* Mattila HR, Otis GW: Dwindling pollen resources trigger the
transition to broodless populations of long-lived honeybees
each autumn. Ecol Entomol 2007, 32:496-505.

This study demonstrated that timing of transition from summer bees to
winter bees can be influenced by pollen availability.

SOURCE:

Döke, M. A., Frazier, M., & Grozinger, C. M. (2015). Overwintering honey bees: biology and management. Current Opinion in Insect Science, 10, 185-193.

* * *

What I think: Resources in fall may be abundant but they are declining. The bees sense the onslaught of the dearth, and manipulate the brood food, deliberately shorting their rations. This switches the bees into the longer lifespan mode, to ride out the winter or dearth. '

We have talked about this before, many organisms all across the range of life forms have this feature whereby when there is a dearth (or anticipated dearth) they forego breeding and go into longer lifespan mode. This new paper demonstrates how this would happen in a bee colony, where the nurse bees are "in charge" of the care and feeding of the next generation of adults. 

If this switch does not occur, we would expect colonies to fail sooner, perhaps in mid-winter like we often see here in Northern US. By the way, I never see so-called dysentery in my hives (I have seen it in other folks' hives). What I often see is a rapid die-off even with adequate honey stores, as if the bees all got old and died. Often the queen is the last bee to die.

PLB

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