Do bees need water?

What colonies use water for

• Evaporative cooling. On hot days water is spread on comb surfaces and fanned, which is how a colony holds the brood nest below 36 °C.
• Diluting stores. Honey is too concentrated to feed directly to larvae, and nurse bees dilute it.
• Brood food. Royal jelly and worker brood food are largely water.
• Drinking. Foragers on a nectar flow get water from nectar; in a dearth they need a source.

Water carrying is a distinct job with its own recruitment. Bees inside signal demand by how eagerly they take water from returning carriers, and the colony adjusts the number of water foragers accordingly.

How to provide it

1. 1Make it shallowA saucer, a bird bath with pebbles, or a bucket with floating cork. Bees drown easily in open water with no purchase.
2. 2Add landing placesStones, marbles, gravel, twigs or corks — anything that lets a bee stand and reach the water without falling in.
3. 3Put it in the sunBees prefer warm water and find it more readily. A shaded dish in a corner will be ignored.
4. 4Keep it topped upBees learn a water source and return to it. If it dries out they will find another, which may be your neighbour's pond or pool.
5. 5Do not add sugarA sugar solution is a feeding station, not a water source, and it encourages robbing and disease transmission between colonies.

The swimming pool problem

Bees are frequently attracted to swimming pools, and once a colony has learned a source it is difficult to move them off it. The practical solution is to establish an attractive alternative before the season starts rather than after, and to make it warmer and more accessible than the pool.

Other bees and water

Solitary bees need far less water and mostly get what they need from nectar. Mason bees are the exception in a different sense: they need mud rather than water, and a patch of damp clay soil within fifty metres of a bee hotel makes the difference between it being used and ignored.