To make her easier to locate in the hive, the queen bee is usually painted with a small dot of colour on her thorax, as shown in this video. The colour also helps the beekeeper to keep track of the age of his or her queens, as a different colour is used for each year in a cycle of five.
White is used for years ending in 1 or 6, yellow for 2 or 7, red for 3 or 8, green for 4 or 9, and blue for years ending in 5 or 0. This system is widely accepted and used by queen breeders and beekeepers the world over. The queen bee in this video is clearly a 2006 model, as her white spot tells us.
It is important to know the age of the queen because her most productive egg-laying time will be limited to the first few years of her life. Queens are commonly replaced every year or two, in order to maintain a strong colony.
This video is courtesy of Brian’s Urban Bees blog, and the bees are residents of Queen’s Park, London, UK.