Royal jelly and how a queen is made

What it is

Royal jelly is produced by the hypopharyngeal and mandibular glands of nurse bees roughly five to fifteen days old. It is about two-thirds water, with proteins — the major royal jelly proteins, of which royalactin is the best known — sugars, lipids including the distinctive 10-HDA, and vitamins.

It is a secretion, like milk. That is worth stating plainly because a good deal of marketing implies it is something bees collect or concentrate from flowers, and it is not.

How it makes a queen

A fertilised honey bee egg is genetically identical whether it becomes a worker or a queen. All larvae are fed royal jelly for the first three days. Worker larvae are then switched to a mixture of pollen and honey; a queen larva continues on royal jelly alone, in quantity, for the whole of her development.

The result is an animal with functional ovaries, a lifespan measured in years rather than weeks, and a completely different body plan — from the same genome. It is one of the clearest examples of developmental plasticity in any animal.

The human-supplement question

Royal jelly is sold widely for fertility, longevity, immunity, skin and energy. The reasoning is almost always the same and almost always wrong: it makes a bee larva into a long-lived reproductive queen, therefore it should do something analogous in a person. Bees and humans do not share the developmental pathway involved, and the proteins are digested like any other protein.

How it is produced

Commercially, colonies are manipulated into rearing large numbers of queen cells, and the jelly is scraped from each cell before the larva consumes it. China dominates world production. It is labour-intensive, and the yield per colony is small — a few hundred grams a season.