A queen excluder is a divider with openings that workers can pass but the queen cannot. Its use is one of the debated topics in beekeeping.

What it does

• Keeps the super free of brood. Harvested comb contains no brood
• Preserves comb colour. Comb never used for brood stays light
• Makes the queen easier to find. The search area is halved
• Provides a division in production. Used in queen rearing and brood interruption

Drawbacks

• It can slow the bees. The resistance to passage reduces storage, particularly in a weak colony
• It causes problems with undrawn foundation. Bees may be reluctant to draw comb above it
• It splits the winter cluster. If left on in winter the queen may be stranded below as the cluster moves up
• It traps drones. Drones above the excluder cannot get through and die

Making it work

• Put drawn comb immediately above it. This encourages the bees to move up
• Fit it when the colony is strong. On a weak colony it markedly reduces storage
• Keep it clean. An excluder clogged with propolis obstructs passage
• Remove it before winter

Types

• Wire: Made of round wires; passage is easier and it damages bees less
• Plastic: Cheap; the edges can wear the bees' wings
• Framed types: Leave a space above, which eases passage

The gap size is critical: too narrow and workers struggle, too wide and the queen passes.

Working without one

Some beekeepers use no excluder. The queen usually stays out of the super; even if she goes up, the brood area stays limited and can be separated at harvest.

This requires less intervention but more care at harvest.

When not to use one

• In winter
• On a weak colony
• When giving undrawn foundation
• In newly established colonies