A nucleus, or nuc, is a small colony on a few frames. It is the beekeeper's most versatile tool and serves many purposes.

What it is for

• Queen mating: The unit in which a new queen emerges and mates
• Spare queens: A ready solution when a queen is lost
• Increasing colony numbers
• A source for strengthening weak colonies
• Swarm management
• Covering winter losses
• Selling colonies

The second is the most valuable: keeping a few nucs in the apiary turns the loss of a queen from a crisis into a routine matter, and saves buying colonies in.

Size

Generally three to six frames. Small types consume few bees but are fragile; larger ones are more robust but need more bees.

It is critical that they take the same frame size as the main hives, so frames can move freely between them.

Features

• A narrow entrance: Against robbing
• Good insulation: A small colony holds heat poorly
• A place for a feeder
• Portability: Light and closable
• Divided types: Several nucs in one body, sharing heat

Setting up

• A frame of sealed brood, honey and pollen
• Moved with the young bees on them; foragers return, so extra bees are shaken in
• A queen, a queen cell or a new queen is given
• Fed if there is no flow

Fragility

Being small, a nuc carries more risk:

• Robbing: The greatest threat
• Heat balance: It may not protect brood on cold nights
• Pests: A favourable environment for wax moth and small hive beetle
• Starvation: With few foragers the stores run down quickly

A nuc therefore needs checking more often than a full hive.

Overwintering

A nuc can be overwintered, but stores, insulation and moisture control are critical. Nucs wintered side by side in a divided hive share heat.

A nuc that comes through the winter is a ready reserve in spring.