What is robbing?
When I wrote this in July, my area’s (southeast Georgia) nectar flow has stopped and all that is available to the bees is some pollen. With foragers going out and returning empty handed, or finding nectar that is sub-par, I find that my hives get a little hot this time of year. When no nectar is available we call this a dearth which basically means there is nothing blooming that the bees will use to make honey.
So, what is a bee to do? The scouts/recruiters of the hive might come across another hive which has honey stores in it and, if the hive is weak, waltz right into the hive following the scent of honey. This foreign bee then quickly tries to get in, get the honey, and get out before being caught by the guards in the hive and removed or killed. If she can escape the hive and return home to her hive, then she will recruit other bees to where she found the honey and since honey is much more attractive than nectar or sugar water the hive can quickly be recruited to go where the original bee located the honey. In no time at all this hive with few guards is in trouble and frantically fighting off these foreign bees which we now call robber bees since they are robbing honey from one hive to bring back to their hive.
How do you know if a hive is being robbed? Signs are very evident: bees fighting at the entrance (usually spinning around on the landing board), multiple bees harassing a single bee, lots of dead bees on the ground, wax flakes on the bottom board, and wax that looks like it has been torn apart in chunks from the capping.
What can you do?
The quickest solution is to close your entrance, reduce it down to the width of a single bee. You can also block the entrance with grass and the bees will remove it over 24 hours and any robbers in the hive will either die or be forced to convert to the hive. Or you can set up a sprinkler to simulate rainfall which will wet the bees’ wings and prevent them from flying.
A robbing screen is the best answer when all else fails.
Last year I tried every single one of those methods and not a single one worked for any length of time so I chose to make my own robbing screens. There are several versions of these, one even as simple as a single piece of hardware cloth folded up, but I wanted to make the screens you see for sale at the bee supply stores for $15-$20. They look simple enough but I could not find a single plan for one on a search so I had to DIY it. I made a run to Home Depot and bought window screen and furring strips. Total cost was less than $10.
Tools you will need: staple gun, staples, measuring tape, pencil, hammer, any type of saw, jigsaw or a drill with hole saws, and nails.
I took the measurements of my bottom board from the side rails that the hive body sits on and marked that on the furring strip and cut two pieces at that length. You will need to measure yours accordingly as manufacturers have slight variations and you want a snug fit.
Once you have the bottom piece cut, cut two more pieces about 4 inches in height (my personal preference, you can make yours longer or shorter).
After that is done, take one of the longer pieces and cut or drill out a small notch in the wood. You want this to be about 3/4 -1 inch so that your bees can easily come and go. I made my entrance hole size too big, next ones I make will be smaller.
Now, nail the two short pieces to the long piece as shown. (Ignore the bottom piece over the screen for now, I did not take any pictures before that piece went on.)
Cut some window screen to size and make sure it is tight against the wood and begin to staple it down. You will need to pull the screen just a little to ensure the screen is snug to the wood.
Now attach the second long piece on top of the screen and attach it to the two short pieces with nails. The reason you have done is that it acts as a support brace at the bottom to hold the integrity of the robber screen as well as keep the screen tight.
Depending on how snug you made your cuts, you may need to use bungee cords to hold the screen in place.
As you can see in the first robber screen I made, on the right, I did not put the bottom brace and it caused the screen to cave in. The bottom brace can also be where you can correct not making the cuts snug enough. If you cut the bottom brace to where you have to jam it into the bottom board side rails then it will prevent needing to use a bungee cord.
Why does a robbing screen work?
The finished product doing what it is designed to do: prevent robbing.
Robbing screens work because robber bees are focused on one thing: the smell of honey. They want to take the quickest route into the hive to be able to rob it out and that route is through the front entrance (unless there are cracks/holes in your hive elsewhere). The robbing screen prevents this because the robbers run into the screen and frantically run around bashing into it trying to follow the scent of the honey but get blocked. The bees belonging to the hive that is being robbed however follow the pheromone scent of the hive to locate the entrance. Because of this they can actually detect the pheromone trail leading out of the front entrance and up to the top entrance hole in the robbing screen: avoiding the robbers and still being able to come and go.
Robber bees never find the pheromone trail because they don’t have the same “smell” as the hive they are robbing. To them the honey is the only thing that exists and we just made sure they can’t get to it.
If you have any questions please feel free to ask.
14 Comments
Thanks I did my own as well I keep mine on my hives at all times I fined it works well. I never have to worry about robbing the window screen was a good idea I was buying the same wire used on the bottom boards and that can be price thanks again
Glad I could help.
These are great! Simple and probably any handy person would have the supplies around the garage/house for quick assembly when needed. Thank you for sharing and saving us some $$! : )
You’re welcome! Thanks for the kind comments.
Can you or would you leave this on all the time? Or just during dearth?
Hi Sharon,
You can leave these on all the time. However, if the nectar flow is really good and you notice a traffic jam then you should take them off as it could impede honey production.
Great article and video. My husband and I whipped one of these up in no time at all. Ours was just a little too loose, but a silver thumb tack pushed into one side helped make it nice and snug. No bungee cord needed. 🙂
Glad it worked well for you; the thumb tack is a good idea (cheaper too)!
It would seem that this setup with screen would also keep out yellow jackets.
I would imagine that wasps would follow pheromone trails the same as honey bees. I never noticed any making their way in when I had my screens in place.
Ok, so, your Mann Lake hive has a top entrance just under the telescoping cover, correct? Can a piece of screen simply be stapled over the front entrance? The pheromone trail should lead to the top opening, right? Wouldn’t this be a simpler solution?
My Mann Lake hives have no top entrance. Some of my supers do have a drilled in hole allowing for another entrance. To answer your question though, honestly I do not know. In theory I would imagine it would but then your whole hive will have to reorient to the top entrance. After they adjust, I would think most of the bees would fan pheromone (and inadvertently the smell of honey) from the top entrance which might negate the bottom screen. The whole idea behind the robbing screen is that robbers are so interested in just following the smell of honey (coming through the screen) whereas the bees belonging to the hive follow the pheromone trail left behind from the bees that know how to get around the screen.
I have had to make some screens at times to prevent robbing of new swarms when I brought them into my yard. Mainly when I removed a swarm and cut out some comb with brood and honey. Fresh smell usually pulls in nearby bees. My screens are nearly like yours but I run them up 9 in. or so. Have worked for me.
Regarding your robbing screen:
Great simple DIY design.
Don’t bees need a hole at floor level to throw out trash, eg dead bees?