Colony Demographics and Brood Breaks

Most folks who read this blog will be very familiar with the life cycle of honey bees and the fact that there are always bees of different stages of development and "ages" in the colony.  There are various tricks and schemes for manipulating bee colonies to serve various purposes (eg, queen raising, maximizing honey production, making new colonies, etc).  I like the ideas of Mel Disselkoen ( http://www.mdasplitter.com/docs/NucManagement.pdf ) and plan to experiment with them.
The basic idea is that the queen is removed from a strong over-wintered hive (used to start a new colony) and the remaining bees are left to raise a new queen.  During the queenless stage the break in brood rearing will discourage any mites and the bees released from brood rearing will be able to collect more nectar which they will store.  The technique results in a fresh queen each year and may help with swarm control.

I have hit upon the following scheme to represent the population of the colony at any given time - presumably after the queen has been laying for a while (say, 6 weeks or more after first Spring flights).  See the following figure.

 What we have here is a vertical chart representing the various "ages" of bees in a colony.  The right-most scale represents the days since the egg was laid and the left-most scale shows the number of days from a given transition.  IE, a transition is from egg to larva, from larva to pupa and from pupa to adult bee.  The color code is to help visualizing which stage any given age is in. The ^^^^ indicates there are more ages but I don't want to estimate them at this time.  This demonstrates that there will never be more than three days worth of eggs, six days of larvae or twelve days of capped brood because even as new eggs are laid, older eggs are hatching to larvae, etc.

For a "normal" queen-right colony, this diagram could represent any day in the history of the colony.  Individual bees in any given age range will move "up" the scale as they age, but the overall picture of the colony will stay essentially the same (at least until autumn and winter).  The Disselkoen procedure is to remove the queen to a new split at a propitious time leaving the old colony to raise a new queen which means egg production and, subsequently, all stages of brood populations will change.  To see what happens to the demographics of the colony, consider the following figure.

Here we started with the population distribution on the final day of the queen laying and started counting from there (bottom scale).  It is easy to visualize that on the second day there will not be any one day old eggs, but there will still be six days of larvae and twelve days of pupae.  As the days pass, all the eggs, all the larvae and all of the pupae will be gone by day 21.  During this period the number of new adults will continue to increase and the population of adult bees will grow considerably (presumably not as fast as the newly emerging bees due to deaths of much older adults).

Clearly this is a recipe for disaster!  But the bees won't let that happen.  Within hours of the bees noticing they are without a queen they will select one or more one day old larvae (four days from the egg) and will start to raise a new queen.  It will take 13 days for a queen cell to ripen and emerge as a virgin.  Most authorities say to figure another seven or so days for her to mature, make her maiden flight(s) and start laying.  The prospects for the colony are shown in the next figure.

Things look bright for the new queen.  There are a lot of bees to care for the new brood, there is a lot of empty cells for her to lay in and within 21 days of this new start there will be newly emerging workers and within 42 days there could be as many as 40,000 adult bees from her laying activities.

We note the gap between the yellow parts of the figure which represents the time in which there are no larvae to be infected with mites and the mites (if any) should suffer a great decrease in their numbers.  We also note that during this time, the worker bees that would normally be taking care of the larvae will have nothing to do and will join the field foragers to bring in nectar - which, also, won't have to be fed to hungry larvae.

Considering the timing, in mid-Missouri an over-wintered hive should (could) be ready to split by mid-April and mid-May at the latest.  If the bees start a new queen in mid-April she would be ready for her maiden flight by the first of May and the weather and availability of drones usually works in her favor.  At worst, she would be going forth by late May.  The colony with the new queen should reach full strength by mid-June to mid-July which is plenty of time to build up for Winter (maybe even produce a fall surplus).