How does a bee colony make decisions?

What the queen actually does

She lays eggs and emits pheromones that signal her presence and reproductive condition. That is essentially the whole job. She does not direct foraging, allocate labour, choose a nest site or decide when to swarm. Workers decide when to replace her, and if they judge her failing they will raise a new queen and kill her.

How a swarm picks a home

1. 1Scouts search independentlySeveral hundred experienced foragers leave the settled cluster and search for cavities, assessing volume, entrance size and position, dryness and exposure. Each scout evaluates on her own, without reference to what others have found.
2. 2Each advertises what she foundA scout returns and dances on the cluster surface, giving direction and distance. Crucially, she dances with a vigour proportional to how good she judged the site — a better cavity gets more waggle runs.
3. 3Support accumulates or decaysOther scouts follow the dances, visit the advertised sites, and dance for them in turn if they agree. A scout also reduces her own dancing each time she returns, so advertising for a mediocre site fades while a good one keeps attracting fresh recruits.
4. 4A quorum triggers the moveWhen enough scouts are at one site — a quorum rather than a majority — the decision is effectively made, the cluster warms up, and the swarm flies to it. The whole process takes hours to days and typically selects the best cavity on offer.

The same pattern elsewhere in the colony

• Foraging allocation. Dance vigour scales with patch quality, so recruitment shifts towards better forage without anyone comparing patches.
• Unloading. A forager who waits too long to hand over her nectar performs a tremble dance, which recruits more receiver bees — a feedback signal about a bottleneck she cannot see the whole of.
• Thermoregulation. Individual bees respond to local temperature with fanning or shivering, and colony-level regulation to within half a degree emerges from that.
• Task allocation generally. Bees shift roles with age and with colony need, responding to local cues rather than to instruction.