Date: Wed,  7 Feb 96 10:32:48 PST
From: [log in to unmask] (Glyn Davies)
Message-Id: <Chameleon.960207103248.buzz@>
Subject:
Date: Tue,  6 Feb 96 21:46:47 PST
From: [log in to unmask] (Glyn Davies)
Message-Id: <[log in to unmask]>
To: [log in to unmask]
Subject: Varroa Distribution
Here in Devon UK we are just coming through our fourth winter with
Varroa. The mite was first identified here in April 1992 at a Club Apiary
in Torquay on the South coast.  Later investigations showed that the
original infestation may have been further in land.  By the end of that
season the mite had been identified in scattered apiaries (bee yards!)
across southern England.  The Government twice drew a line making it
illegal to transport bees or equipment to the North.  These were not
observed by the mite and the line is soon to be redrawn for the third
time towards the Scotland/England border.
 
Maps published during the last four years show the advance of Varroa.
Its spread appears to be in the direction of UK's strongly prevailing
summer/autumn winds.  That is from the south west. The mite has moved
hundreds of miles to the northeast but Cornwall, just to the south west
of Devon is relatively free and the few known cases can be traced to
beekeeper movement of hives.  Wales is also quite free of Varroa so far
and would be  outside the flight-line of "wind-blown, mite-contaminated
bees" .
(A map of UK will help those not familiar with our geography!  Draw 2
lines a)from Gloucester in the west to Norwich in the east; b)the Devon
/Cornwall border.  The area between these lines is the heavily
contaminated area at 20 Nov 1995; Wind direction from S.west; Origin of
infection Dartmoor in the County of Devon. The Department of Agriculture
moved the infected area line from a)above to a line from Newcastle in the
N.east to Gloucester on 1.1.95.  It should be moved again soon but
Wales and some North west areas still want to be protected by being kept
outside the line.)
 
Questions/Theories:
1. Are swarms more likely to migrate in the direction of the prevailing
wind?  Are the preceding scouts more likely to search  "downwind" than
"upwind"?
2. If hives are infected as a result of robbing, do robber bees tend to
attack weak colonies that are upwind as a result of say, more easily
detected alarm/fear pheromones or the scent of poorly protected or
exposed stores?
3.  How is Varroa distributed apart from movement by beekeepers? Drones
are known to drift considerably but do they carry Varroa?  Do they drift
with the wind?
 
I regret this message is so long.  Living with Varroa makes you realise
your lack of knowledge of basics even after years of beekeeping.
 
PS. Nobody I know supports the theory of Bumblebee involvement.