[Hobo]

Last year I had a hive that for some reason a huge number of bees preferred to live clustered under the screened bottom board. Try as I might I could not get them to move into a box. Both of last year's hives died over the winter.

One week ago I got four nucs and installed them. These nucs came from a completely different source than last year's bees. And, just like last year, I am having a tremendous robbing problem. I installed robber screens on all four hives in the evening after the bees stopped flying. The next day I noticed a number of bees who could not figure out how to get back inside their hives due to the screens. On a couple of these hives a lot of the bees had clustered under the screened bottom boards. I assume they chose to gather there because they can smell and see "home". So I slid in the debris board under each hive to close off the screened bottom boards. (I was also hoping to reduce the odor of honey and sugar syrup coming from the hive through the SBB and attracting robbers.)

Today when I inspected the hives I noticed that one hive - curiously the one in the same location as last year's hive with the bottom dwellers - had a large number of bees between the bottom board screen and the debris board. The entire space was full of bees. Hundreds and hundreds of bees. I don't doubt that I trapped a few bees when I slid in the debris board several days ago but those bees should be dead by now. Somehow these bees found their way into this small space. I slid the debris board out and smoked them but the bees did not want to leave the screened bottom board. So I got another bottom board (screened but with the debris board in place) and another brood box and moved all the frames to the new box. I temporarily left the robber screen off the new box so the stragglers could find their way back into the hive. When I left them a clump of bees was hanging from a front corner of the old bottom board.

Now it is dark and several hours after I moved the frames to the new box. A small cluster of bees (fist size) are between the screen and 4X4 support post and a small number of bees are on top of the screen to top off that clump of bees. I guess they prefer being under the screen to being inside their hive.

No, I don't think a queen is in that clump of bees. I found no evidence that my hive had swarmed plus I found the queen during the inspection and she was safely placed in the new box.

Why do my bees have a propensity to cluster under the bottom board screen? Is this a common problem with SBBs? Is robbing made worse due to using SBBs? Should I leave the debris boards in place all the time to try to prevent the bees from clustering under the bottom board and to control odors to reduce robbing? Are screened bottom boards just a bad idea? Should I replace all my bottom boards with solid bottom boards?

 

[Riverderwent]

Why do my bees have a propensity to cluster under the bottom board screen?

Is there a terrain or landscape feature near or affecting the location where the problem hive is causing odd wind currents (most likely from the south)?

Are screened bottom boards just a bad idea? Should I replace all my bottom boards with solid bottom boards?

Yes. Yes.

 

[Vance G]

SBB's are a royal PITA and serve no real purpose. A bottom board entrance on a solid BB and an upper entrance or just an upper entrance will allow the bees to ventilate things just fine. When your home AC is working especially hard do you open a couple windows to cripple the machines ability to circulate hot air out of the house?

 

[Hobo]

Is there a terrain or landscape feature near or affecting the location where the problem hive is causing odd wind currents (most likely from the south)?

No. This hive faces south and in that direction it is mostly open (former pasture) then trees about 20 to 30 yards from the hive.

Yes. Yes.

SBB's are a royal PITA and serve no real purpose.

Thanks for confirming what I have come to conclude. When I bought my equipment I had no experience and knew only what I had read. And what I read said SBBs were helpful in controlling varroa mites. So far SBBs have been a PITA for me because of bees clustering under the screen and refusing to move. And I suspect SBBs have had a hand in attracting robbers to my hives.

Thanks, Vance. The ventilation thing always bothered me. There is such a thing as too much ventilation.

And what about light? Bees like it dark. That huge opening in the bottom of the hive lets in plenty of light.

 

[Greeny]

Is this a common problem with SBBs?
I'm a newbee too, so my advice is probably worth what you pay for it. My first two hives gave me fits with this too. I installed the debris boards, and they squeezed through the gap at the center of the boards and packed in under the screen.

Is robbing made worse due to using SBBs?
I think it certainly alerts other hives, wasps and hornets to the location of a large supply of food. But if the debris boards are removed it also distracts the robbers from the hive entrance. I haven't had any real problem with robbing if the hive is healthy.

Should I leave the debris boards in place all the time to try to prevent the bees from clustering under the bottom board and to control odors to reduce robbing?
That's what I ultimately did on my first two hives. And I used push-pin tacks to secure the gaps, front and back, and keep the bees out of the space between the debris board and bottom screen. All my additional hives have solid bottom boards.

Are screened bottom boards just a bad idea?
They are ok for me, as long as I keep them secured and tight, front and back. It is relatively easy to pull the tacks and remove the debris board for a look at whats dropping through. But I now prefer solid bottom boards. A couple times I have had the debris board out, and after reinstalling it been distracted by something (squirrel!), and forgot to put tacks back in. Bees find the gap and start piling in. Once a few bees get in there, a bunch more start joining them.

Should I replace all my bottom boards with solid bottom boards?

You don't need to replace them, but take some extra effort to make the front and rear gaps bee-tight. Some people swear by them and make them work, but I've found they just aren't needed for additional ventilation or cooling in my area. My bees do perfectly fine with solid bottom boards and it's one less worry or hassle for me. You may be a little warmer and more humid than me, but not by much. I didn't replace my original two, but I now leave the debris boards in place year-round and my additional hives (4) are all solid bottoms. I

 

[Oldtimer]

Life is so much simpler with solid bottom boards.

 

[Marcin]

I don't have an answer to your problem, but I've had bees take up residence underneath screen bottom boards in the past a few times. In all cases it involved a virgin queen coming back from mating and somehow not making it into the hive. They've even build comb and started raising brood in there.
As for screen vs solid bottom discussion, I started out with screens and started using solid more and more. Up until this spring, I was leaning towards solid bottoms. But this winter/spring, my 3 winter dead outs were all on solid bottom boards, and the rest of the hives with solid bottoms look weaker than those on screens. Not making any judgment calls here, just sharing observations.

 

[Mike Gillmore]

I installed robber screens on all four hives in the evening after the bees stopped flying. The next day I noticed a number of bees who could not figure out how to get back inside their hives due to the screens.

This might be part of the problem. Rather than using robber screens you may want to try temporarily reducing the entrance so it's easier for the bees to guard it. Start over with an entrance reducer instead of a robber screen. Maybe prop up the cover just a fraction of an inch to allow for upper ventilation if the bees need to circulate air through the hive.

Remove the box and set it aside, shake or brush all of the bees off the sbb. Insert the board and put duct tape across the opening and seal it off for now. Put the bottom board back in it's original location and add the hive body with an entrance reducer.

The entrance may get a little congested until you remove the reducer later on, but sealing off the sbb opening will stop the bees from searching for another way to get into the hive.

 

[Alex Madsen]

Did you use lemon grass oil on any of this equipment? That can cause strange clusters due to it mimicking queen pheromone.

 

[JWPalmer]

As to the SBB vs. solid debate, I have always used screened bottoms here in VA and the bees do just fine. I think there is more to it than merely selecting one over the other. I do not get a significant number of bees under the screen, but it is not uncommon for there to be a handful or more during the day. I use the inserts during the cooler months but may start leaving them in year round. When I clean them, once per week, usually no more than one or two dead bees, about what one would expect. I would definitely remove the robber screens until the hives get settled and use an entrance reducer. Use the small opening if robbing appears to be a problem. After a week or so, you should be able to put the robbing screens back on if needed. I figure if a colony is strong enough to be in a 10 frame box, a robbing sceen should not be necessary. I only use them on my nucs.

 

[Hobo]

Did you use lemon grass oil on any of this equipment?

No.

 

[pjs1inc]

Did you figure out how to solve the problem? I had the same issues

 

[Oldtimer]

The solution is easy, don't use screened bottom boards use solid ones.

 

[pjs1inc]

The solution is easy, don't use screened bottom boards use solid ones.

Thought about that but we are now in the mid 90s and very high humidity, not sure the bees would survive. Even with the screen bottom there are a ton of them outside bearding 24 hours a day. Thunder stormed yesterday and they didn't bother to go in the hive!