# Nuc Growth - How much difference with a screened split board?



## Boxelder (Sep 16, 2017)

Hello All

A common technique for making nucs is to put them on top of a large colony, seperated by a screened split board. The idea is that the heat rising from the large colony will help the nuc expand its brood nest more quickly. What is the consensus - does that really make much difference in how quickly the nuc expands? In other words, is this technique well worth doing?


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## fieldsofnaturalhoney (Feb 29, 2012)

In CA, may not matter much, but in CO, it gives me a much earlier opportunity to make healthy, warmer splits prior to the last frosts. 17 degrees tonight. However, the larger you make the splits the less shared heat is needed?


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## Boxelder (Sep 16, 2017)

fieldsofnaturalhoney said:


> In CA, may not matter much, but in CO, it gives me a much earlier opportunity to make healthy, warmer splits prior to the last frosts. 17 degrees tonight. However, the larger you make the splits the less shared heat is needed?


Thankyou for the reply, fields. Is it possible that their is also some nutrient exchange across the screen via tropholaxis that would facilitate nuc buildup?


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## fieldsofnaturalhoney (Feb 29, 2012)

Boxelder said:


> Is it possible that their is also some nutrient exchange across the screen via tropholaxis that would facilitate nuc buildup?


I would think not because you would need to use a double screened board, which prohibits the colonies from “touching” one another & keeps there pheromones separate..


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## Akademee (Apr 5, 2020)

Queen pheromones are transmitted by touch, thats why this method works. The double screen prevents any bees from being able to touch each other. The main reason for all of this is heat conservation and putting waste heat to work. Very effective if done correctly. Some people even overwinter nucs like this. This would be very effective in the winter, but outside of the cold season, there would be almost no benefit.


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## Boxelder (Sep 16, 2017)

Akademee said:


> Queen pheromones are transmitted by touch, thats why this method works. The double screen prevents any bees from being able to touch each other. The main reason for all of this is heat conservation and putting waste heat to work. Very effective if done correctly. Some people even overwinter nucs like this. This would be very effective in the winter, but outside of the cold season, there would be almost no benefit.


It is conventional wisdom that a double screen is needed, but are we certain of that? Some split boards designs apparently have only a single layer of screen, and would seem to work just fine. See these web links from the UK that explain the dimensions of a "Horsley Board"

hivemindandme.blogspot.com/2016/06/bulding-horsley-boards.html

http://www.dave-cushman.net/bee/horsleybd.html


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## crofter (May 5, 2011)

Boxeld;

There does seem to be some controversy over this issue. Some people claim that even an excluder will instigate emergency cells. Some say and excluder and two honey supers between the queen and a box of young brood will trigger it. Snelgrove suggests the excluder, and several supers separation then install the double screen board creates more of a supercedure response rather than emergency. 

I know nothing about the original bee of the UK at the time of writing much of the old literature but have read that there exists considerable difference in habits compared to say Carniolan bees. Could race or species of bee contribute to the discrepancy?

Some pheremones seem to be airborne and others tracked around and some exchanged by swapping gum. I dont know which sort are most determinate in regard to signalling queen + or Queen -

I have never had the double screen snelgrove fail to trigger cell starting but haven,t tried one single screened. I have had the excluder only separation fail to start cells. It would be interesting to see if there were appreciable difference in effectiveness.


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## odfrank (May 13, 2002)

I do not use them for heat transfer or promoting the division, but to reduce equipment needed, and easy merging when no longer needed. I have had the bottom portion die off more often than the top portion when leaving together all winter. I wonder if that has to do with mite drop? They are also convenient for ventilation when moving the divides. My medium depth double queen castles are on divisions screens.
This hive last week had a queen below he excluder, a queen above the excluder and all boxes so full of brood, bees and honey we did not even try finding the queens. We split the brood chamber boxes from the honey supers with a divisions screen and separated all boxes with excluders. We will go back in three weeks and get the queen out of the honey supers. I am now also placing my bait hives on top of the weakest hives with a piece of plywood and a division screen. Division screens are a great tool.


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## Boxelder (Sep 16, 2017)

Thankyou all for the informative replies. It sounds like there might be some opportunity here for some more research. Certainly a single screen division board would be easier to build, and if the colonies could still share resources via tropholaxis, there might be some really powerful benefits in building up week colonies!


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## Gray Goose (Sep 4, 2018)

odfrank said:


> I do not use them for heat transfer or promoting the division, but to reduce equipment needed, and easy merging when no longer needed. I have had the bottom portion die off more often than the top portion when leaving together all winter. I wonder if that has to do with mite drop? They are also convenient for ventilation when moving the divides. My medium depth double queen castles are on divisions screens.
> This hive last week had a queen below he excluder, a queen above the excluder and all boxes so full of brood, bees and honey we did not even try finding the queens. We split the brood chamber boxes from the honey supers with a divisions screen and separated all boxes with excluders. We will go back in three weeks and get the queen out of the honey supers. I am now also placing my bait hives on top of the weakest hives with a piece of plywood and a division screen. Division screens are a great tool.


Frank, have you actually caught swarms in the top with the screen in place?
This is a great way to save bottoms and tops.

GG


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## odfrank (May 13, 2002)

This is the first year I am trying that and not far along in the season to have data. I have reports of scouts on them. I think the dark round hole if an actual bait hive might be better, which is what we did last year. But I am trying to avoid the frame transfer. I will report with more data in a few weeks.

[/QUOTE]

Frank, have you actually caught swarms in the top with the screen in place?
This is a great way to save bottoms and tops.

GG[/QUOTE]


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