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Author Topic: Brood Death Tempatures?  (Read 710 times)

Offline GSF

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Brood Death Tempatures?
« on: July 19, 2013, 08:38:20 PM »
I know that if the temperature gets below a certain point it will kill off the brood. What about hives out in the direct sunlight on very hot days? Is there a natural hot temperature that will kill them off as well?
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Offline BlueBee

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Re: Brood Death Tempatures?
« Reply #1 on: July 20, 2013, 03:22:12 AM »
Any living thing will croak if it gets hot enough.  I do not know what temp the bees will croak at but I do recall reading some beeks in the Ukraine (or somewhere over there) killing the varroa mites off with a heat treatment of about 115F for 20 minutes or so (don’t recall exact times).  That supposedly cooks the varroa before it cooks the bees.  It may be a thermal mass kind of thing.  The smaller mass of a mite is going to move up in temp toward 115F quicker than a fat bee.

It was 95F here today.  It was MISERABLY hot :(.  My bees are mostly all in foam insulated hives though and hence they’re not going to get much above ambient temps because the hives are not going to experience a solar gain with 1.5” (40mm) of foam between the HOT sun rays and the bees. 

Offline shinbone

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Re: Brood Death Tempatures?
« Reply #2 on: July 20, 2013, 07:44:06 AM »
Not sure at exactly what temp brood dies, but the bees maintain the temperature of the brood nest between about 92F and 97F (the range varies by a degree or two depending on what study you read).  Presumably this means that the brood would die if the temperature exceeded that range by more than a degree or two.
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Offline sawdstmakr

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Re: Brood Death Tempatures?
« Reply #3 on: July 20, 2013, 08:00:42 AM »
Here is some information on Japanese bees and the Japanese giant hornets and the temperatures each can tolerate.
Bee predation
In Japan, beekeepers often prefer European honey bees because they are more productive than the endemic Japanese honey bees. However, it is quite difficult to maintain a captive hive of European honey bees, as the hornets will often prey on the bees.
Once a Japanese giant hornet has located a hive of European honey bees it leaves pheromone markers around it that quickly attract nest-mates to converge on the hive. A single hornet can kill forty European honey bees in a minute; a group of 30 hornets can destroy an entire hive containing 30,000 bees in a little more than three hours. The hornets kill and dismember the bees, returning to their nest with the bee thoraxes, which they feed to their larvae, leaving heads and limbs behind. The hornets also eat the bees' honey.
The Japanese honey bee, however, has a defense against these attacks. When a hornet approaches the hive to release pheromones, the bee workers emerge from their hive in an angry cloud formation containing some 500 individuals. They form a tight ball around the hornet that acts like a convection oven when the bees vibrate their wings to direct air over their bodies, warmed by their muscular exertion, into the inside of the ball. The interior temperature of the ball rises to 47 °C (117 °F). The hornet can survive maximum temperatures of 44–46 °C (111–115 °F), but the bees can survive up to 48–50 °C (118–122 °F), so the hornet is killed and the bees survive.
Jim
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Offline sc-bee

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Re: Brood Death Tempatures?
« Reply #4 on: July 20, 2013, 08:53:43 AM »
Never heard of brood or bees dying from heat set up in a hive in a field etc.  as the bees can fan to circulate some amount of airflow. Have heard of them dying from heat while moving them without proper ventilation.
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Offline Finski

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Re: Brood Death Tempatures?
« Reply #5 on: July 20, 2013, 11:35:22 AM »
.
However, larvae do not stand much cold. That is why youd should not open a hive on cold day or lift brood frames off from hive.

First what they do is that they get chalkbrood.

If it is cold, bees retreet from peripheria and brood will be destroyed.

Bees keep very accurately the temp in brood area. So we can conclude that brood do not stand much deviation.


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Offline L Daxon

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Re: Brood Death Tempatures?
« Reply #6 on: July 20, 2013, 12:13:07 PM »
Here in central Oklahoma we can get summer temperatures near or above 110 degrees. (Not this summer, thank goodness). I think that is one reason hives are painted white, to reflect the heat.  The girls I am sure keep the dark brood nest cooler than the outside temps by the use of fanning and moisture release, but you will occasionally see a honey frame that will "melt" from the combination of heat and the weight of the honey if it is not wired well.  The wax doesn't really "melt" as it takes about 142-144 degrees for wax to melt, but it softens enough that the weight of the honey pulls the foundation out of shape and downward into a big mess.

The heat issue is one reason my hives back up to the east side of my house, so they get early morning sun but are shaded in the afternoon.  But now that I think about it, since my house is brick and my hives sit on a 10x15 concrete block slab I made for them, I am sure they get some radiated heat from the brick even though they are in the afternoon shade.
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Offline sc-bee

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Re: Brood Death Tempatures?
« Reply #7 on: July 20, 2013, 04:48:46 PM »
Not uncommon at all for wireless foundation to release from frames because of the weight of honey or brood and warm temps. I see it myself here in SC. Not 110 but 97-103 range frequently and a humid heat with the air heavy, Rough :-P

When you say pull out of shape in a mess does it still remain attached but kind of drip? Just honey frames I am guessing or brood too? Man that is hot  8-)
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Offline L Daxon

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Re: Brood Death Tempatures?
« Reply #8 on: July 22, 2013, 12:05:36 PM »
When "melting" honey frames pull away, usually from the top and sides they can kind of fold over on themselves and break open some of the capped honey cells, then you have honey dripping down.  The girls can and will clean that up.  But it is when you go to pull the melted frame that you can create an even bigger mess if the frame had melted/folded into the frame(s) next to it.  Of course this usually happened (if it happens) on newly drawn foundation--I use some of that really thin cut comb foundation--and not in the brood frames which definitely tend to stiffen up over time and are usually wired.

That being said, this year, for the first time, I am having terrific luck with the black pierce plastic frames.  I teach the beginning bee class in central OKC and I have always told my students that the bees don't like the plastic nearly as well as the regular wax foundation but this summer has made a liar out of me and my girls have been drawing out the pierce stuff every bit as fast as regular foundation in wood frames, even when they are side by side.  Go figure.
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