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Date: | Mon, 2 Aug 2010 09:18:02 -0400 |
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>> >The surface of the cluster is a dangerous place for varroa
> Interesting conjecture... I can't hardly imagine that a healthy mite would drop through or over a layer of bees without catching hold.
Then why do we see live mites on the bottom board?
Of course, on top of any cluster, a mite would fall past more bees than on the bottom of a cluster. In either case, though, mites falling or being brushed off on the bottom fall free.
Anyhow, it only takes a small influence on average varroa lifespan to reduce the slope of a upward population curve or turn it downwards, and this is only one of the differences between small and large clusters.
Diameter Area (A) Volume (V) A:V Ratio
1-----------3----------- 1-------------6.0
2----------13-----------4-------------3.0
3----------28-----------14-----------2.0
4----------50-----------34-----------1.5
5----------79-----------65-----------1.2
6----------113---------113----------1.0
7----------154---------180----------0.9
8----------201---------268----------0.8
9----------254---------382----------0.7
Here is a 6" cluster compared to a 17" cluster
6----------113---------113----------1.0
17---------908--------2572---------0.4
The surface area increases less than half as quickly as the volume.
Geometric effects in scaling are under-apreciated.
Small clusters tend to have less drone brood and for shorter duration as well.
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