"Subject: Varroa mite biology

I am interested in finding out how long the varroa mites are in the phoretic
stage on the bees after the bee emerges until those mites enter cells to
breed. How quickly can this happen and/or is there an average time?
Tom"

Hi Tom and All,
When varroa first arrived in Auckland NZ, maybe 2 or 3 years ago, I had very
high mite levels in many hives. The NZ Govt. provided Apistan strips for the
first (and second) treatments, I had mine put in on the 21 Aug 2000. I then
counted the 'mite fall' and graphed it. I don't have the 'Math.s power' to
interpret the data but I think it may help answer your question. Mind you,
as the conditions change, so the interpretation probably should change as
well. BUT hard data is hard data and should have some explanation, even if
the interpretation is debatable.
Data,
1. In the first 2 or 3 days, 4000 to 6000 mites fell (say +or-2000) then
2. The graph plateaued at 1500 mites/day (+/-100 say) until day 12 then
3. the graph dropped and plateaued again at 50 mites/day (+/-5) until day
26, then
4. plateaued again at 7 mite/day (+/-2), but
5. the graph did not decrease to 1 or 2, it stayed at about 6 until the
apistan strips were removed on day 44.

I thought that the reason for the first plateau was that 1500 mites were
hatching from the cells that had been capped prior to the apistan
application.
The second plateau at 50 mites/day was that say 40 pregnant mites of the
1500 mites, managed to get into a cell and be capped, thus avoiding being
'apistaned'. That is 40 of the 1500, say 1 in 38 (or 40), avoid poisoning.
The third plateau at 7 mites/day was say 5 pregnant mites of the 50, that is
5 of the 50 or 1 in 10 avoid poisoning.
1 in 40 when their are a lot of mites, and 1 in 10 when their are much less.
Does this make sense?

The reason the mite fall never reached 0, 1 or 2, could be the apistan
becoming expended, or as the supplier says, these are 'incoming mites'. What
do you reckon?

One could also argue, that there are say 5000 mites either 'walking' 'W' or
'attached to a bee' 'A' in the bee colony. These come from the 1500 mites
that hatch from the capped cells, 'C mites', each day. Does this mean that
5000/1500 = say 3 is about the average time a mite spends outside a cell, as
a 'W' or 'A' mite? 3 days?
OK?
Cheers Paul b. Auckland, NZ.