Is it a swarm cell or a supersedure cell?
During spring build-up, beekeepers often search for swarm cells in order to determine if the hive is preparing to swarm. But what is a swarm cell and how is it different from a supersedure cell?
First of all, the term “cell” usually refers to an oversize structure attached to the comb in which a queen will be raised. This can be confusing to new beekeepers, because there are regular “cells” all over the place—in fact, a comb is nothing more than a series of interconnected hexagonal cells. Confusing as it may be, however, when beekeepers talk about “cells” they are usually referring to queen cells.
Drone cells are often in the vicinity of swarm cells but should not be confused with them. Drone cells usually occur in groups at the edge of the frame, and there may be hundreds of them. They are much bigger than worker cells, and some people describe them as “bullet-shaped,” although I would guess the people who use that term have never seen a bullet. I would describe the surface of drone cells as “pebbly” or like cobblestones. In any case, the surface is rounded whereas worker cells are flat on top.
Queen cells are very different. When completed, they look like a peanut shell—rough-textured, elongated, perhaps an inch overall (2.5 cm), and they hang vertically off the frames. Once you see a completely finished and capped swarm cell it is usually too late to stop swarming, so you have to learn to identify them before they are finished. In their unfinished form they are called queen cups. Queen cups are prepared for the existing queen to lay eggs in.
Now, more confusion. The term “queen cup” is also used by beekeepers to describe a commercially manufactured product that is used to raise queens. Their purpose is the same—a place to lay an egg that will be raised as a queen—only the commercial ones are made of wood, plastic, or perhaps wax. The ones you are looking for are made by the bees and have been described by others as “teacup” shaped—although I think they look more like tiny bowls. After an egg is laid in a cup, the cell is enlarged into the “peanut” shape by the workers.
Now, in case there are people who can actually follow this description, I’ll add another layer of confusion. A cell hanging off the middle of the frame somewhere is usually a supersedure or “emergency” queen cell. A cell hanging off the bottom of a frame is usually a swarm cell.
Supersedure cells are often begun after the eggs are laid. The bees, knowing they need to replace the queen, begin feeding royal jelly to a young larva they have selected. They build a supersedure cell around this larva (or several larvae) and it hangs down from the face of the comb. Swarm cells, however, are built in preparation for swarming and are not intended to replace the queen, but to raise a second queen. This way, there will be a queen for the part that swarms and a queen for the part that stays.
If a colony is in two brood boxes, the swarm cells will almost always be found hanging from the bottom of the upper row of frames between the two boxes. When beekeepers hunt for swarm cells they frequently just tip up the upper brood box and examine the bottoms of the exposed frames.