A Slatted Rack and Robbing Screen Can Improve Your Hive Entrance
Optional Extras for Your Langstroth Beehive
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One of the best things about a Langstroth beehive is its adaptability. By using optional pieces of beehive equipment like a slatted rack and robbing screen, you can adapt your beehive to suit local conditions. Some beekeepers do fine without any optional equipment, but others find some pieces extremely useful, depending on the problems they face.
What is a Slatted Rack?
A slatted rack, also called a brood rack, is a piece of woodenware about two inches deep with the same outer dimensions as your Langstroth beehive. It consists of a series of parallel wooden slats that run in the same direction as the frames. On the entrance end of the hive, the slats fit into a four-inch wide flat board that runs across the width of the hive. The entire rack fits between the bottom board and the first brood box, forming a false floor. Slatted racks come in sizes to fit 8-frame or 10-frame equipment.
The original slatted rack, developed more than 100 years ago, had slats running crosswise under the frames. But today’s slatted racks are designed to be used with screened bottom boards. Each slat lies directly under a frame, and the empty space between slats is directly beneath the space between frames. The design allows varroa mites and other hive debris to fall directly to the screened bottom board and out of the hive.
How Does a Slatted Rack Help Your Bees?
The main purpose of a slatted rack is to provide an insulating pillow of air below the brood chamber. The false floor is a clever compromise that gives the bees more living space but prevents them from building comb below the brood nest. The extra space helps keep the honey bees cooler in summer and warmer in winter.
In summer, when the brood nest can get too warm, the slatted rack give the bees a place to congregate which spreads the heat load and reduces bearding on the outside of the hive. If your hive is on a stand, you can look up from underneath on a warm day and see thousands of bees congregating on the slatted rack. Because slatted racks lessen congestion in the brood nest, some people believe they also reduce swarming.
The slatted rack moves the brood nest further from the bottom board by two inches. For overwintering colonies, this dead air space provides insulation from the cold bottom of the hive and keeps the drafty entrance further from the nest. In summer, it allows the queen to lay eggs lower on the combs because the combs are further from the sunlight and drafts that flow in through the hive entrance.
From a human perspective, a slatted rack provides a place to hang out, trade jokes, and sip iced tea for a few minutes before going back to work in the heat of the day. Even bees need an occasional break.
Robbing Screens Protect Your Bees
A second piece of optional equipment that alters the hive opening is a robbing screen. A robbing screen fits over the regular entrance and provides an alternate entrance for your bees to use.
If you are new to raising honey bees, you will soon discover that robbing is one of the most difficult disruptions for a beekeeper to handle. Robbing begins when social insects such as wasps or other honey bees discover a poorly protected stash of food. If they can overpower the guard bees, they will go inside the hive and take everything. Robbing bees will steal the honey, fight with the resident bees, and even kill the queen. Robbing wasps will also kill the bees and the brood, taking it back to their own nest to feed their young. Once robbing begins it is notoriously hard to stop, so the best remedy is prevention.
Robbing screens prevent robbing by making the entrance confusing. Although the residents of a bee hive know where the entrance is, robbing bees try to find the entrance by smell. You can often see them sniffing around any place where the scent of the colony is leaking from the hive. They examine the junctions where two boxes meet, the area under the lid, or any holes or splits in the wood of the hive. They keep testing all the places that smell right until they eventually find the opening.
Many beekeepers try to handle robbers by reducing the entrance to the smallest possible size so there is less opening to defend. But this is one of the worst things you can do. When you reduce the opening, you are making it easier to find because all the hive odors are coming from one small space. Every sniff leads the robbers to the right place.
How a Robbing Screen Works
A robbing screen fits over the entire front of the hive. The space directly over the real entrance is usually solid and an alternate entrance is placed on the other end of the frame, usually at the top. The rest of the frame is screened or perforated to release the hive scent. Using their own pheromones, the residents of the hive soon learn where the new opening is. They will come in through the new opening and then go down to the old opening behind the solid part of the robbing screen to enter their hive. In the meantime, the robbers keep following the scent and bumping into the screen over and over in a futile attempt to get inside.
Watching the robbers trying to get through a robbing screen is mesmerizing. It seems that at any moment the robbers will discover the opening and overwhelm the hive. But it doesn’t happen. Bees are wired differently than mammals, and what makes sense to us apparently doesn’t work for them. In the event that any random robber does make it in, the resident guard bees quickly take care of it.
Robbing Bees and Varroa Mites
Many beekeepers have begun using robbing screens year round because they also keep out drifting bees. Drifting honey bees may be workers that lose their way home, drones that don’t care which hive they enter, or bees that are fleeing a dying colony. Both drifting bees and robbing bees can spread varroa mites and pathogens into other colonies.
However, just as robbing screens keep out robbing bees, they can effectively keep out the drifters. It is still unclear how many mites are introduced by drifting and robbing bees, but some researchers think it is substantial. In any case, a robbing screen can help you control it.
Think about your own colonies. Are there ways a slatted rack or robbing screen could help you become a better beekeeper?