Development from egg to emerging bee varies among queens, workers and drones. Queens emerge from their cells in 16 days, workers in 21 days and drones in 24 days. Only one queen is usually present in a hive. New virgin queens develop in enlarged cells through differential feeding of royal jelly by workers. When the existing queen ages or dies or the colony becomes very large a new queen is raised by the worker bees. The virgin queen takes one or several nuptial flights and once she is established starts laying eggs in the hive.