Beekeeping
The queen is the only sexually mature female in the hive and all of the female worker bees and male drones are her offspring. The queen may live for up to three years or more and may be capable of laying half a million eggs or more in her lifetime. At the peak of the breeding season, late spring to summer, a good queen may be capable of laying 3,000 eggs in one day, more than her own body weight. This would be exceptional however; a prolific queen might peak at 2,000 eggs a day, but a more average queen might lay just 1,500 eggs per day. The queen is raised from a normal worker egg, but is fed a larger amount of royal jelly than a normal worker bee, resulting in a radically different growth and metamorphosis. The queen influences the colony by the production and dissemination of a variety of pheromones or "queen substances". One of these chemicals suppresses the development of ovaries in all the female worker bees in the hive and prevents them from laying eggs.
Royal jelly
The honey bee queens and workers represent one of the most striking examples of environmentally controlled phenotypic polymorphism. Even if two larvae had identical DNA, one raised to be a worker, the other a queen, the two adults would be strongly differentiated across a wide range of characteristics including anatomical and physiological differences, longevity, and reproductive capacity. Queens constitute the female sexual caste and have large active ovaries, whereas female workers have only rudimentary, inactive ovaries and are functionally sterile. The queen–worker developmental divide is controlled epigenetically by differential feeding with royal jelly; this appears to be due specifically to the protein royalactin. A female larva destined to become a queen is fed large quantities of royal jelly; this triggers a cascade of molecular events resulting in development of a queen. It has been shown that this phenomenon is mediated by an epigenetic modification of DNA known as CpG methylation. Silencing the expression of an enzyme that methylates DNA in newly hatched larvae led to a royal jelly-like effect on the larval developmental trajectory; the majority of individuals with reduced DNA methylation levels emerged as queens with fully developed ovaries. This finding suggests that DNA methylation in honey bees allows the expression of epigenetic information to be differentially altered by nutritional input.