Bees undertake a developmental journey known as complete metamorphosis. This biological process involves four distinct forms: egg, larva, pupa, and adult. Each phase represents a significant transformation, allowing bees to grow and mature from a tiny, immobile stage to a winged, functioning member of a colony.
The Egg Stage
The bee’s life begins when the queen lays a single egg at the bottom of a hexagonal cell within the comb. These eggs are small, typically 1 to 1.5 millimeters long, resembling a tiny grain of rice.
The egg stage lasts approximately three days for all bee castes. The type of bee that develops—worker, drone, or queen—is determined by whether the egg was fertilized. Fertilized eggs become females (workers or queens), while unfertilized eggs result in male drones.
The Larval Stage
After three days, the egg hatches into a larva, appearing as a tiny, white, legless grub. These grubs are blind and unable to feed themselves, entirely dependent on worker bees for nourishment. The larval stage is characterized by rapid growth and consumption of vast quantities of food.
Nurse bees, which are young worker bees, are responsible for feeding the larvae. All larvae initially receive royal jelly, a protein-rich secretion from worker bees, for their first two to three days. For worker and drone larvae, the diet then switches to “bee bread,” a mixture of pollen and honey. Queen larvae, however, continue to be fed royal jelly throughout their entire larval development.
As the larva grows, it sheds its skin multiple times, a process known as molting. A bee larva undergoes about five molts, significantly increasing in size with each. Within about five days, a larva can grow to be over 1,500 times its original size. The larval stage usually lasts about six days for worker bees, slightly longer for drones, and a bit shorter for queens.
The Pupal Stage
Once the larva is fully grown, it stops eating and prepares for the next transformation. Worker bees cap the cell with a wax lid, sealing the larva inside. The larva spins a cocoon around itself, resembling how a caterpillar forms a chrysalis. This marks the beginning of the pupal stage, a quiescent period of internal and external changes.
During this stage, the pupa does not consume food; instead, it relies on stored nutrients. The pupa begins to take on the familiar form of an adult bee, initially appearing white and immobile. Its eyes are typically the first features to develop color, progressing from pink to purple and then black. Legs, wings, and other body parts gradually take shape and become visible externally.
Tissue reorganization occurs internally, with larval tissues breaking down and adult structures forming. The pupal stage duration varies by caste: approximately 7.5 days for queens, 12 days for workers, and 14.5 days for drones. This metamorphosis leads to a fully formed adult bee.
The Adult Bee
Upon completing the pupal stage, the fully developed adult bee chews its way through the wax capping of its cell to emerge into the hive. The type of adult bee that emerges—queen, worker, or drone—depends on the egg laid and the feeding during the larval stage. These three castes have distinct roles within the colony.
Worker bees, non-reproductive females, constitute the majority of the hive’s population and perform almost all the labor. Their tasks change as they age, a phenomenon known as temporal polyethism. Young worker bees spend their first few days cleaning cells and the hive, then transition to nursing, feeding larvae and the queen, often between 3 to 12 days old.
As they mature, worker bees take on roles such as processing nectar, building and repairing comb, and handling debris. Older worker bees, typically after about 21 days of age, become foragers, venturing outside the hive to collect nectar, pollen, water, and propolis. They also serve as guard bees at the hive entrance, protecting against intruders.
The lifespan of adult bees varies significantly by caste. Worker bees generally live for about five to seven weeks during active summer months, but can survive for several months during winter. Drones, the male bees, primarily serve to mate with a queen and typically die shortly after mating or are expelled from the hive before winter. A queen bee, responsible for laying eggs, can live for several years, often between one to four years in managed hives.