I have one or two observations - I opened one of my (modified TBH) hives
last week (before it snowed!) to find a good amount of stores throughout
the colony, ie some honey on nearly every comb, plus some brood on the
middle two combs, and towards the end furthest from the entrance solidly
honey. They had obviously stored more than they needed for winter. There
were 17 top bars.
This is a TBH, but double-walled with featherboard for insulation on the
outside, and with Warre-type quilt boxes plus a pillow in the eke. (See
oxnatbees.wordpress.com/2014/03/27/adding-warre-features-to-a-top-bar-hive/)
The floor is open mesh but with a bottom board which is raised beneath the
floor, and over winter the debris from chewing off wax cappings has made a
carpet over the mesh, effectively insulating the floor. Ventilation still
happens because at the ends, beyond the follower-boards, the mesh is clear.
Going into winter I thought this hive had not really prepared with adequate
stores, but it seems their motto was better late than never. I have not fed
them. In fact I just removed three bars of honey.
My other similar hive has a bigger colony, but I couldn't inspect them as
they were completely propolised-up. What I did manage to see was that the
six-or-so bars nearest the entrance were empty of bees - they were all down
the further end on the remaining 12-or-so bars.
Helen
On 18 March 2018 at 17:05, Paul Honigmann <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
First, sorry for not yet commenting on your earlier post on survey
results. It's on my to-do list...
To "advantages of warm hives" Derek Mitchell (the expert everyone quotes)
would add "*vastly less fuel needed* to maintain optimum humidity / temp*
for honey manufacture* in summer". Ie it's not that they are WARM hives
but WELL INSULATED and it helps in all seasons.
Re: disadvantages. Through the windows I've sometimes seen bees in a loose
cluster with some wandering around comb when the books say they should all
be in a tight cluster. Presumably that uses more energy than simply
clustering, but I'm guessing not *much* more as the bees seem to thrive
in well insulated hives, and they never seem to use as much winter stores
as the BBKA say they need (maybe 5-7kg not 20kg). Also in general I would
say the bees I see have relatively small winter clusters, nothing near the
size you hear of in conventional books (a winter cluster covering several
frames). So despite the brood rearing being earlier / easier than in a cold
hive, one can say "it works".
A minor advantage of Warres is that OSR honey is said to still be liquid
after 2 years, i.e. easily eaten by the bees, instead of crystallising in
weeks and this is thought to be due to the honey being kept continuously
warm.
Perhaps the most telling experimental proof of warm hives' benefits is
that Gareth reckoned his bees struggled in TBHs but thrived when he
switched to Warres. He knows his stuff and has lots of hives. Warres are
definitely better insulated than TBHs, but they differ in other ways too
(vertical structure vs horizontal) so this isn't a controlled experiment.
However, assuming that Gareth lives in a marginal area where bees struggle
- and I would say rural west Oxfordshire is not ideal as there are long
nectar dearths and a lot of monocropping - it shows that *something*
about the hive types makes a positive impact. Gareth is now experimenting
with other hive types like the einraumbeute
<http://www.dheaf.plus.com/framebeekeeping/modified_einraumbeute.htm> to
see how they modify the bees' behaviour, but he keeps returning to heavily
insulated ones, i.e. Warres with extra thick walls or double walls.
Paul
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On 18 March 2018 10:51 AM, Will H <whanrott@xxxxxxxxxxx> wrote:
I've heard Paul say on several occasions that insulation is good for hives
because it ensures a warmer hive. I would like to develop a better
understanding of the advantages and disadvantages of hive insulation. I'm
writing to the group for views. Please pitch in.
So far...
Advantages of warmer hives:
- lower energy requirements over winter limits risk of starvation
leaves colonies in better condition in the spring
- winter brood rearing will provide younger workers who can help the
colony increase in spring
- Varroa mites may preferentially infest brood cells at cooler
temperatures, so higher temperatures may inhibit Varroa reproduction[1]
- fewer cold surfaces may reduce condensation which limits mould and
spoilage by yeasts
- bees are able to move around the hive to access stores during the
colder months
Disadvantages of warmer hives
- warmer brood nest may stimulate winter brood rearing which increases
energy requirements and may leave colonies at greater risk of starvation
- winter brood rearing provides a host for reproduction of Varroa
whose numbers will be greater in spring
- winter brood will be heavily infested by Varroa because there are
fewer of them. This may lead to disabling levels of Deformed Wing Virus. I
already see noticable numbers of crawling bees in spring because of this.
These new bees are wasted effort for the colony
- condensation may be useful for metabolising honey over winter. Bees
may need to fly for water when none is condensing in the hive and risk
being lost
You'll see that some of the advantages have -- as I see it -- a
corresponding disadvantage. Furthermore, I wonder whether discussions about
warmth may be conflating better insulation with reduced ventilation. It may
be that better insulation is good but worse ventilation is bad but you
can't have both.
All comments are welcome.
Thanks
Will
[1]: From "Biology and control of Varroa Destructor", Rosencrantz et al
2009: "Depending on the test system Varroa mites prefer temperatures
between 26 and 33 °C (Le Conte and Arnold, 1987, 1988; Pätzold and Ritter,
1989; Rosenkranz, 1988), which are significantly lower than the normal
temperature in the brood nest of approximately 34.5–35 °C (Becher and
Moritz, 2009; Rosenkranz and Engels, 1994). Varroa mites are able to
discriminate temperature differences of about 1 °C (Le Conte and Arnold,
1987). It was assumed that Varroa females preferably invade colder brood
cells at the periphery of the brood nest; however, there is no solid
evidence for this hypothesis and the preference for low temperature may, at
least in part, be due to the artificial test conditions in a laboratory
temperature gradient (Dillier et al., 2006)."
