When a honeybee colony loses its queen, workers instantly feed royal jelly to a young larva to transform it into a replacement. The colony builds emergency queen cells, and after five days the virgin queen emerges, mates in flight, and takes over the hive.
When you take a queen bee out of a colony, they immediately try to replace her by feeding a young larva with royal jelly. This stimulates the young larva to turn into a queen, and then you find in the colony emergency cells like this. Once these emergency cells are ripe, virgin queens will emerge and they'll fly out after about 5 days, go and get mated, and hopefully become the new mated queen of this colony.
