Queen Cell Cups

A queen cell cup (commonly called a queen cup or cell cup) is a small, bowl-shaped container facing downwards that forms the start of a queen cell; in nature bees build it of wax at the edge of the comb, while beekeepers use artificial cups made of plastic or beeswax in queen rearing and royal jelly production. The bees feed the young larva grafted into the cup as a future queen and extend the cup into a complete queen cell. The shape, size and cleanliness of the cup directly affect the acceptance rate.

What is a queen cell cup?

Honey bee colonies, especially in spring and the swarming season, build small, round, downward-facing wax bowls along the lower and side edges of the combs. These are natural queen cups. Most remain empty; if the queen lays in one of them and the bees feed the larva with plenty of royal jelly, the cup is extended into a queen cell.

An artificial cell cup imitates this natural beginning. Instead of waiting for the queen to lay, the beekeeper transfers a chosen young larva into the cup (grafting). This puts the beekeeper in control of which breeder stock is used, when, and how many queens are reared.

How does a queen cell develop?

A queen cell differs from worker and drone cells: it is not hexagonal, but a large, rounded structure hanging downwards, perpendicular to the plane of the comb. When mature its surface becomes rough, resembling a peanut shell. Development proceeds as follows:

1. Cup: A shallow, bowl-shaped start. The grafted larva or egg lies at the bottom of this bowl.
2. Extension: Once the larva is accepted, the bees extend the mouth of the cup with wax and fill it with plenty of royal jelly.
3. Capping: The cell is capped about 5 days after grafting.
4. Maturation and emergence: The queen emerges about 11–12 days after grafting; ripe cells are distributed on day 10.

Types of queen cell cup

Features of a good queen cell cup

• Size: Its inner diameter and depth should be close to those of a natural cup. Grafting is harder in a cup that is too narrow; in one that is too wide the bees spend extra effort narrowing the mouth.
• Uniformity: Cups in the same batch being identical gives even feeding and cells of equal size.
• Inner surface: Smooth, burr-free, with no sharp mould marks at the bottom.
• Material: Odourless, food-grade plastic or clean, residue-free beeswax.
• Compatibility: It must fit the holders, bars and cell protectors you use.

How are queen cell cups used?

1. Prepare: Arrange the cups on holders or directly on the bar; give new plastic cups to a colony for about a day before grafting so the bees clean them.
2. Graft: Place the youngest possible larva, less than 24 hours old, at the bottom of the cup together with the jelly beneath it, without turning it over.
3. Get them accepted: Give the bars to a queenless, crowded starter colony.
4. Finish or harvest: In queen rearing, accepted cups are moved to a finisher and distributed on day 10; in royal jelly production, the jelly is collected after about 72 hours.

How can you tell a cup has been accepted?

If you look at the cups about a day after grafting, the accepted ones have mouths that have started to be extended with wax, and their insides are shiny and full of jelly, with the larva floating on top. A cup that has not been accepted looks empty or dry, or its larva has been removed. Maturing cells become long, large and rough-surfaced.

What do natural queen cups tell the beekeeper?

Seeing empty natural cups in the hive is not a sign of swarming on its own; many colonies keep empty cups throughout the season. But the presence of an egg, or a larva in jelly, inside the cups shows that the colony has started rearing a queen. In that case the possibilities of swarm preparation, supersedure or queen loss must be considered; details are given on the swarming and supersedure pages.

Cleaning and storage

• Plastic cups: After use, wax and jelly remains are cleaned off; they are washed in lukewarm water, rinsed thoroughly and dried.
• Beeswax cups: Unused ones are kept in a closed box in a cool, dark place; used wax cups are melted down.
• Disease: Cups used in a colony showing signs of disease are not used in another colony.
• Odour: Cups are not stored with treatments, fuel or strong-smelling products.

Common mistakes

• Grafting older larvae: However good the cup, an older larva does not produce a good-quality queen.
• Mixing cups of different sizes: This gives uneven feeding and inconsistent results.
• Dirty or smelly cups: One of the most common causes of low acceptance.
• Mounting cups too close together: Ripe cells stick together and are damaged when separated.