!

Those of us who kept bees through the initial collapse of feral populations
due to varroa remember the effect well--our colonies, made nearly mite-free
by application of Apistan strips, were simply overwhelmed by an influx of
mites from the collapsing feral colonies.

Today, the same likely happens in urban areas containing large numbers of
treatment free beginning beekeepers.  As their colonies collapse from
varroa, they flood the neighborhood with mites by drifting and robbing
behavior of bees.


I have been pondering this for months now.   While some of what Randy points
out makes perfect sense in areas with many yards, the math of the mite
counts going up in hives does not work in what I consider to be the average
area. 
Here is why.  Please point out my errors in thinking.

The base assumption is that mite numbers are doubling or better.  That would
entail pretty close to literally every mite from a collapsing hive to
immigrate (depending on the number of brood cycles after immigration and
before  the count)  
This also would require that roughly 1/2 the hives in a given area
collapsed.  This is something I have never seen.  Fall collapse (aug/sept)
are non existent here. Always some failure to thrives, but they don't
collapse until later in the season. Those hives with high mite counts are
starting to fail, but given deformed wings are a main source of this issue,
obviously these bees will not be part of the problem.

Given the higher number of mites on nurse bees, this theory also requires
the mites to make a jump to foragers and pack the traveling bags. It seems a
stretch that mites do this as a matter of intent.  Yes I realize that
younger and younger bees are recruited to forage, but also recognize they
don't all drift to other hives.

Alternative thought, 2 fold,  first as mentioned elsewhere  the amount of
bees drops a bit,  thereby increasing the infestation rate,  and secondly
and I think much more mathematically viable,  is the slowdown in brood
chamber temps.  A lower temp will increase the capped time by 24 hours  this
is going to allow around a 25%increase in the number of mites per cycle,
about 2 rounds of that and you have a huge issue,  and on top of that the
increased mite load (5 mature mites instead of 4) means that the brood
survivability dropped and again back to less bees per mite.

It seems to me to prove or disprove, would take a bit of genetic monitoring
of mites..  In the end I am not sure it really matters.  But it is an
interesting discussion.  It seems to me the studies so far show a snapshot
in time and location.  Dr. Seelys work seems closer to what I think the
majority of the country sees.   I was looking at his work on Drifting in
general,  I did not see his work on drifting as it pertains to mite load
increase? 

Charles

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