Robin said:

> Peter's 120 hives seems to offer a good sample for testing the
> theory that just a few hives at random can suddenly show abnormal
> high Varooa infestation  (due probably to robbing an infected colony),
> if all the hives are individually monitored?   Can I ask if they are?

Let's assume that Peter is a very fast and efficient worker,
and can remove a board, estimate a relative varroa count,
and slide in a new sticky board in 3 minutes per hive, total.

   120 * 3 mins = 360 mins
   360 mins / 60 mins/hr = 6 hours

Let's also assume that Peter is very fast at preparing
new sticky boards, and can prepare each in 1 minute.

   120 * 1 min = 120 mins
   120 mins / 60 mins/hr = 2 hours

So, if Peter were to use and check sticky boards on all his
hives weekly, it would consume a full 8-hour workday every week!!

This problem of "scale" often appears with many good ideas
that are advocated by people who manage smaller numbers of hives.
Problems with "scale" tend to show up when one starts to manage
around 50 hives - the burden of even small inefficiencies starts
to become a real pain.

> whilst drifting drones carry enough Varooa to infect a previously
> clean area, drones represent so small a proportion of all bees that
> drifting does not have much effect on re-distributing mites within
> an infected apiary.

Colonies weakened by varroa get robbed by bees from uninfested colonies.
Those bees come back bearing both goodies and mites.  Capture and mark
returning foragers landing at 2 or 3 healthy hives using a different color
for each hive, and then go watch the landing board of a weak hive in the
same area.  You will see many pretty colors.

                        jim

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