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>From:    Allen Dick <[log in to unmask]>
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>One thing about polystyrene is that it does not breathe at all.  I wonder
>what kind of entrance reducers you use and if you use top ventilation
>and/or flight holes.
>
>I know that in Europe, in some regions where polystyrene hives are common,
>that beekeepers don't use top entrances.
>
Now Allen, you are not going to start that old discussion again are you?
We had it about every winter since I joined the list some 8 years
ago..... ;-) I think we just agreed to disagree and leave it by that. I
know of no one that uses upper entrance here, and it seems compulsory on
your side of the pond. We don't use entrance reducers either.

When bees consume sugars they produce CO2 and water. That has to be
transported out of the hive some way. CO2 is heavier than air and thus
sinks to the bottom of the hive (if the hive is properly sealed up at
the top so no draught is causing unwanted movement of air inside). On
Styro hives we normally use a mesh bottom (about half the area of the
bottom board) open all year. And leave the entrance open, it's kept 8 mm
high to keep mice out. This works perfectly well here and uses the bees
normal instinct to seal up everything above them with propolis for winter.

On the other side, you make a small hole at the top and reduce the
entrance to cause a upward draught through the hive and lead CO2 and
water out trough the top hole instead. Same thing done different ways.
Difference can be feed consumption during winter. From what I read on
the List you leave up to 35 kg of feed in the hives. That would equal
around 28 kg dry weight of sugar. Usually we leave 12 to 20 kg dry
weight for winter. The difference is not due to climate, when the same
goes for the far north of Sweden with low temps and a very long winter.
It is probably due to the extra feed needed to keep cluster warm in the
constant draught of cold air.

There are other advantages with Styro hives. Murray and others has
pointed at most, but there is one I like to comment on. That's the
perfect fit between the parts. On wooden hive parts you always get
buildup of propolis when wood is a living material and swell and bend
after the moisture content. Bees fill up those cracks and a layer is
constantly getting thicker causing changes in size. Not so on plastic.
It keeps clean when bees don't have any hole or crack to seal. It's not
changing in size due to moisture swelling, and this means in practical
work much less problem with burr comb between boxes and makes everything
faster and easier when working bees in the field.

No commercial beekeeper would consider buying wooden boxes here anymore.

Something totally different; I have been fiddling with the Varrox
evaporator and oxalic acid treatment lately. Got a few pix on the
subject, and hopefully some data on efficiency if the winter isn't
coming too fast and stop me. I remember you asking about this earlier.
http://www.algonet.se/~beeman/research/oxalic/oxalic-1-nf.htm
This page will change as I get more data to post there, hopefully in a
couple of weeks. I'm comparing vaporizing with trickling of sugar-oxalic
solution on 24 hives. Hope to be able to get Apistan strips in to check
remaining mites before winter.
--
Regards

P-O Gustafsson, Sweden
[log in to unmask]  http://www.algonet.se/~beeman/