Once a new queen has emerged in the colony she is not yet ready to lay eggs. The queen must take a mating flight and mate with several drones. The queen will then return to the hive and begin to ley eggs. The process of mating flights and subsequent ovary development can take approximately 13 days. Several things like weather can interfere with the mating flights. Also a queen may take several test flights before the actual mating flight.
Once a queen is mated and her ovaries are developed, she begins to produce pheromones. The other worker bees are extremely keyed into this pheromone. You can see a huge difference in the attention that the worker bees are giving to these two different queens. One queen has been mated and her ovaries are developed while the other is not.