Click Here if you listened. We’d love to know what you think. There is even a spot for feedback! Read along below!
By: David Burns
Have you ever inspected your hive and had to separate two brood boxes only to find a large amount of gross-looking torn open brood in between the top and bottom boxes? When you lift a top brood box, you are often breaking open bridge comb filled with larvae and pupae and now they are all exposed. Most often it is drone brood. What should you do? Should you remove it? Leave it for the bees to clean up? Or better yet, how can you keep this from happening altogether?
Our traditional hive is called a Langstroth hive because, around 1851, Rev. Langstroth observed that honey bees maintain a gap of 1/4” to 3/8” (6-9 mm) to allow them to move around the hive. As beekeepers, we call this bee space. Beekeepers quickly learn that when you violate bee space, the bees will fix it, but you won’t like how.
If smaller than bee space the bees will add propolis to seal the gap. Bees will build comb when the space is larger than bee space. It’s called burr comb because the word burr refers to things that are rough, irregular, or sticking out like a burr left on metal after cutting it. When comb sticks out in odd places we call it burr comb. But when bees use comb to connect two surfaces we call it bridge comb. Think of it as comb being used to bridge a gap. In this case, it is burr comb, but more specifically since it is bridging a gap, it’s bridge comb.
What should you do when you see exposed brood in the bridge comb? I’ve learned through experience that if I use my hive tool to scrape it off as soon as I see it, this usually causes my bees to quickly become defensive. The destruction of brood, in this case, on top of the frame bars is still seen by the bees as destructive and they don’t like it. Just imagine the phenomes that are triggered by the injured larvae and pupae as you scrape it off. My first choice is to leave it, especially if it’s only a small amount.
When I’m making YouTube videos and this happens, I receive so many comments asking me what it is, what happened and what will I do. If I must clean it off, it must be the very last thing I do after the inspection just before I place the top box on. This will minimize the amount of time the hive is open, and the bees show me their dislike of what I have done. I also carry a metal can with me during inspections just for this purpose. You do not want to drop this in the bee yard, as it can potentially attract unwanted pests and varmints you don’t want around or in your hives.
What causes this? I have noticed it is caused mainly by the top frames not being in alignment with the frames in the bottom box. You can see this in my illustration. The easiest way to align all frames in all boxes is to make sure frames in each box are pushed toward the middle leaving the extra and equal gaps next to the wall. If you are unsure, you can give a quick peak to see before placing a top frame in the top brood box.
Mismatched boxes from various manufacturers can cause this as well. Some manufacturers will make their frame rests slightly deeper or higher. This is fine if you use the same boxes in the same hive. But if one frame rest is higher and another box is lower, there will be a gap between the bottom of the top frame and the top of the bottom frame that violates bee space and the bees will place bridge comb in this area. In older boxes the frame rest area can become lower as we frequently scrape out propolis year after year. Even the part of the frame that rests on the frame rest can be thicker or thinner according to the manufacturer. Most beekeepers have an assortment of brood hive boxes that are different enough to allow this bridge comb to appear quite frequently.
It all comes down to bee space. Try leaving a frame out and see what happens. On second thought, don’t. It’s not good. Respecting bee space helps your bees avoid wasting energy building unnecessary comb and raising brood you will likely remove. A little attention to frame alignment goes a long way.
If you’d like to watch my video where I explore this topic more visit: https://www.honeybeesonline.com/davids-youtube-channel/
