Rick responded to Jane's question about re-queening.  In Montana, our
most of our migratory beekeepers re-queen every year, usually in the
spring.  Those who don't migrate generally re-queen once every two
years.  As Rick pointed out, introduction of a new queen shouldn't cause
too much disruption, unless they reject the new queen.  Then you will
have to try again.  References such as the Hive and the Honey Bee cover
all of the pros and cons of re-queening using various methods of
introduction.
 
However, your concern brought to mind a somewhat different observation.
Whereas re-queening in the spring or fall should not cause too much
disturbance, allowing a colony to go queenless and then to count on
the bees to replace the queen can create a fair amount of drop-out of
brood production and according to our field observations and model
simulations can have a much greater impact on honey production.
 
The reason is fairly simple.  If you kill and replace a queen, hopefully
the period during which no eggs are being produced is limited to a few
days.  If the old queen is lost (she dies, gets squashed, etc.) and the
bees have to replace her, the down period may be several weeks.
Assuming the bees weren't taking steps to replace the queen before she
quit laying or was lost, it will take them about 12-14 days to produce a
replacement, who must then mate, and later go to work laying-eggs.
Minimally, there will be a two week period with no eggs.  However, it is
unlikely that a new queen will mate and start laying on the same day that
she emerges, so realistically, it may be about three weeks before any new
eggs are produced --- and --- another three weeks before any new forager
bees emerge.
 
Depending on whether the "lost" queen was laying well to the end or maybe
not laying much at all, the period of time over which no new bees (of any
numbers) could range from 3-6 weeks.  Assuming that a poor queen may lay
1000 eggs per day, a normal queen closer to 2000, and a really good queen
upwards of 3000 eggs per day (during peak egg-laying periods), the effect
on overall population size can be substantial.
 
Take home message, queen replacement should not be too disruptive and can
be beneficial in terms of maintaining colonies with vigorous queens.
Letting the bees do it extracts a much greater penalty.  Depending on the
time of year, the impact can be substantial, especially is the old queen
is lost at a time when the colony is striving to increase its population
size in anticipation of the coming growing season.  Losses of queens
after the major honey flow has been collected may not be a problem, if
the bees have enough time to replace the queen before going into winter.
 
Jerry Bromenshenk
University of MT
 
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