Young nurse bees secrete royal jelly from their hypopharyngeal and mandibular glands and pack it into brood cells. Every larva gets royal jelly for its first ~3 days; after that, larvae destined to become workers are switched to a diluted mix of honey and pollen ("worker jelly" / beebread), while larvae in specially built, peanut-shaped queen cells keep receiving pure royal jelly throughout their larval life. That sustained diet — rich in proteins such as royalactin — is what pushes a genetically ordinary female larva onto the queen developmental track: bigger body, functional ovaries and a queen's much longer lifespan.
The biology above — glandular secretion and diet-driven caste determination — is well established in honey bees. The health claims sold around royal jelly supplements in humans are a separate question: clinical evidence in people is much thinner, mostly small or short trials, and results are mixed rather than conclusive.
Nurse bees secrete royal jelly from glands in their heads and pack it into brood cells — every larva gets it briefly, but only larvae kept on it continuously develop into queens. This lab lets you dial that diet duration and watch a larva's growth and fate respond.
A worker-shaped hex cell and a peanut-shaped queen cell are fed side by side. The worker-cell larva's "royalactin exposure" climbs while it stays on pure royal jelly and decays once switched to worker jelly, driving its final size and caste outcome.
Set how many days the worker-cell larva gets pure royal jelly, adjust the nurse bees' secretion rate and the simulation speed, then watch the exposure, body size and jelly-pool readouts update as the cell caps and resets.
The chemistry that makes this possible is mostly water — royal jelly is roughly two-thirds water by mass, with proteins, sugars, fatty acids and trace vitamins making up the rest, shown in the floating composition ring.