The queen bee is the only female in the colony capable of reproduction. She looks similar to the workers, but her abdomen is larger. Queens take 16 days to grow from an egg into an adult. Within 10 days of emerging as an adult, the queen will go on a mating flight where she will mate with up to 14 drones. She can then store the sperm from those drones and use it to fertilize her eggs for the rest of her life, which is on average 3 years. The queen is the mother of all of the bees in the hive. She can lay up to 2000 eggs a day! Some worker bees, called attendants, take care of the queen. They will feed her, clean her and tell the rest of the colony how the queen is doing using pheromones.
Image: A Queen cell and a Queen among Worker bees.
When the queen becomes old or is not laying as many eggs as she used to, the worker bees will replace her. They will choose a few young female larvae and feed them royal jelly, which is a secretion from a gland in the worker bee’s head. This diet is what makes a female larva grow up to become a queen instead of a worker. The first of these queens to emerge becomes the new queen. She will then find the other queens and sting them before they can emerge. Finally, she will find the old queen and sting her as well.
Worker bees make up most of the population in a colony. As their name suggests, worker bees do all the work in the hive. They are responsible for collecting food and water, building comb, cleaning, raising larvae, protecting the hive, and caring for the queen. All of the workers are female! Workers take 21 days to grow from egg to adult and live for up to 6 weeks. The workers that are produced in the late fall are called “winter bees” and can live four to six months as the colony overwinters. Worker bees do not have fully functioning reproductive organs like the queen does, but in some cases, can lay eggs in the absence of the queen. This is called “laying worker syndrome”. Workers will only lay unfertilized eggs, so only drones will be produced in a laying worker hive.
Different groups of worker bees will have different jobs in the hive. Nurse bees are in charge of caring for the larvae and cleaning the hive, guard bees defend the hive entrance from intruders, and foragers collect nectar, pollen, water, and propolis.
Drones are the male honey bees in the colony. They are much larger than worker bees, have no stinger, and have very large eyes. They have excellent sight! Drones are produced from late spring to mid summer. They take 24 days to grow from egg to adult and can live for 3 months. A drone’s only function is to mate with a queen from outside its hive. Each day, drones will leave the hive in search of a queen to mate with. They will travel up to 5 km to areas called “drone congregation sites” which are places that drones from multiple colonies will come together in search of a queen. If the drones are unsuccessful, they will return to their hives and try again later. If a drone does mate with a queen, they die immediately after. At the end of the summer, the worker bees will kick the drones out of the hive to prepare for winter. There is simply not enough food for them in the fall and winter.
Sex determination: Haploid vs Diploid
A queen can control if she lays a male or female egg. It is determined by the size of the cell that she is laying the egg in! If the cell is small, the queen will lay a female egg, and if the cell is large, she will lay a male egg. Female eggs are fertilized, and male eggs are unfertilized! Queens have a special organ called the spermatheca that she stores sperm from the drones she has mated with. Female eggs are fertilized as they are laid. Because only the female eggs are fertilized, worker bees have half the genetics of the queen, and half the genetics of one of drones that the queen mated with. This is called diploidy (having 2 sets of chromosomes). Since male eggs are unfertilized, done bees only carry the genetics of the queen, which is called haploidy (having 1 set of chromosomes). Drone bees are clones of the queen!