Temporal polyethism

A female solitary bee, such as Ceratina flavipes (a carpenter bee), leads a busy life. She builds the nest, lays eggs, feeds the developing larvae, provisions the nest with stored pollen, defends it against parasitic wasps, and seals it securely for overwintering.

But, if you experimentally force two C. flavipes females to share a nest, they spontaneously divide the workload. One lays the eggs and guards the nest, and the other becomes non-reproductive and does the foraging.

A similar separation of roles is seen when ant queens are forced to share the same nest; one lays eggs, and the other does the next excavation.

These are examples of a reproductive division of labour. It doesn't evolve. Instead, it happens immediately. It is an innate feature of sociality.

Some readers may be familiar with this; if you mow the lawn, you probably don't also do the ironing. That's not a reproductive example (obviously!), but it is a division of labour.

It is thought that natural variation between the individual carpenter bees (or ants) accounts for this division of labour; one is more 'reproductive', the other more adapted for foraging.

Honey bees exhibit a similar reproductive division of labour; the queen lays the eggs, and the workers … do the work.

But there's a lot more work to do in a honey bee nest containing 30,000 workers, 10–20 kg of stores and pollen, thousands of developing larvae and pupae, and consisting of an architecturally complex 3D structure.

They achieve this by exhibiting an additional division of labour, an age-related one. Individual workers belong to one or more temporal or behavioural castes — nurses, guards, foragers — and these vary, both over time and between bees.

Scientists term this age-related division of labour 'temporal polyethism' {{1}}.

It is essential for colony survival, but it is something that is disrupted during natural processes like swarming, or unnatural events like a Pagden artificial swarm, or populating mini-nucs.

Or, in fact, most major hive manipulations.

What accounts for temporal polyethism, how is it maintained, and how is it restored after these natural and unnatural events?

Finally, is it relevant to practical beekeeping, or can we just safely (but gratefully) ignore it?

We can ignore it, but perhaps we shouldn't.