# Maximum gap size to still keep bees out



## Rader Sidetrack (Nov 30, 2011)

I don't have a direct answer to that, but this guide to _hardware cloth _sizes may be helpful:



Michael Bush said:


> #8 - no bee can pass. pollen gets stuck.
> #7 - as long as there are no bent wires, no bee can pass. Pollen falls through
> #6 - worker bees can squeeze through (and will) but they have to wiggle and squirm a lot. Drones and queens cannot.
> #5 - worker bees can squeeze through easily but lose some of their pollen. Queens and drones cannot.
> #4 - all bees can pass (workers, drones and queens). The workers sometimes lose some of their pollen when they catch their basket on the wire. (mice cannot and this makes a nice mouse guard)


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## jbraun (Nov 13, 2013)

I tried using 2 pieces of 1/4" or #4 cloth for my screened bottom. The problem with this was the two piece didn't exactly line up so there were bands where there was 1/4" available for the bees to get through. I found some 1/8" #8 hardware cloth at a hardware store and replaced it and it works to keep all bees out. 

I'm assuming you want to make a screened bottom board. If this is correct you will staple the hardware cloth directly to the wood of your bottom board and you will have no gaps.


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## Rader Sidetrack (Nov 30, 2011)

Tim is attempting to make an in-hive _bug zapper_ that will zap SBH, but not bees. He needs a gap that admits beetles, but not bees.


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## mgolden (Oct 26, 2011)

Think it is 1/8. When using 1/8 screen for screening for moving hives, there is the odd bee that sqeezes through.


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## KQ6AR (May 13, 2008)

I think these zappers will work great since the beetles like hiding places. Was thinking about making one also.



Rader Sidetrack said:


> Tim is attempting to make an in-hive _bug zapper_ that will zap SBH, but not bees. He needs a gap that admits beetles, but not bees.


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## TimStout (Feb 5, 2014)

Radar, thanks, I had seen this table before but couldn't find it.

Hardware cloth of 6-mesh, standard wire size, apparently has an opening of a nominal 0.132". I will assume that if a bee needs to twist and squirm to get through a screen of this size, that a tunnel with extended walls spaced this far apart would be effective in keeping bees out. As far as 8 mesh screen goes, a bee would need to be a contortionist to get through that. So, I need to make sure that my gaps are no bigger than 0.132 inch. Fortunately, I have a mill which allows me to make a gauge of this exact thickness, so the quality control becomes making sure the gauge does not freely pass into the gap.

ANOTHER QUESTION: DOES ANYONE KNOW if guard bees are less fully developed and hence smaller than foragers, or if they have already reach full size by the time they start chasing SHB around? I am not worried about occasionally losing a bee. Typically, about a thousand bees die a day of old age, and I would thank that even if it cost one bee per beetle killed, a hive would be better off at that loss rate than have the constant stress of trying to corral and control the beetles. However, I do not want any beetles to get stuck within a zapper. So, the issue of the size of guard bees is important.

I will ship a zapper inserted in an inner cover to a test site tomorrow. If the results are worth reporting, I will report and possibly have some pictures, hopefully within a week or so. I hope the shocker lets small hive beetles do some bungee jumping from the inner cover to the bottom of the hive. Except, of course, the beetle will not have the bungee cord and will be stunned/paralyzed for about ten minutes or so. That will allow him to pass through the screened bottom and into an oil pan waiting for him. At the test site there are two hives with known SHB infestations in them and which collect SHB on a regular basis. The first test is to see if the shocker gives a significantly increased rate of accumulation of beetles in the pan. 

If the test results warrant, I should very shortly be making a Kickstarter (www.kickstarter.com) project out of this.


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## Michael Bush (Aug 2, 2002)

>ANOTHER QUESTION: DOES ANYONE KNOW if guard bees are less fully developed and hence smaller than foragers, or if they have already reach full size by the time they start chasing SHB around? 

Small cell bees will be smaller. Guard bees vs foragers will also be smaller, but not in the thorax and that seems to be the limiting factor. They can squeeze their abdomen (and they can swell it by filling up on nectar) but they can't squeeze their thorax.


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