Worker bees are the most numerous inhabitants of a honey bee colony, frequently observed diligently working inside and outside the hive. Their collective efforts are fundamental to the community’s survival. While typically sterile, worker bees possess ovaries and can lay eggs under specific conditions. This article explores their roles, the biological mechanisms that usually prevent their reproduction, and the rare circumstances when they do.
The Worker Bee’s Essential Tasks
Worker bees perform diverse tasks crucial for the colony’s functioning, transitioning through different roles as they age. Younger worker bees begin as nurse bees, feeding developing larvae with royal jelly, honey, and pollen. They also attend to the queen, grooming and feeding her.
Worker bees also contribute to the hive’s physical structure by producing beeswax and building honeycomb, which is used for storing honey, pollen, and eggs. Other internal duties include processing nectar into honey and packing pollen. Older worker bees transition to external roles, becoming foragers that collect nectar, pollen, water, and propolis. Worker bees also act as guards, defending the hive entrance, and as fanning bees, regulating the hive’s temperature.
How the Queen Controls Reproduction
In a healthy honey bee colony, the queen bee is the sole reproductive female. Her presence maintains social order and reproductive division of labor within the hive through chemical signals called pheromones. Queen mandibular pheromone (QMP) is a complex blend of compounds produced in her mandibular glands.
QMP spreads throughout the colony as worker bees in the queen’s retinue groom and feed her, then transfer the pheromone to other nestmates through contact. This chemical signal inhibits the development of worker bee ovaries. Specific components of QMP, such as 9-oxo-2-decenoic acid (9-ODA) and 9-hydroxydecenoic acid (9-HDA), are effective in this ovarian suppression. This pheromonal control ensures the queen’s reproductive dominance and colony cohesion.
When Worker Bees Lay Eggs
Worker bees can develop their ovaries and lay eggs when the queen’s influence is absent or diminished. This occurs if a colony becomes queenless or if the queen is failing and not producing sufficient pheromones. The absence of queen pheromones and brood pheromones removes the inhibitory signals that normally suppress worker ovary development. It can take several weeks after the queen’s loss for workers to begin laying eggs.
Eggs laid by worker bees are unfertilized because worker bees do not mate. These unfertilized eggs develop exclusively into male bees, known as drones. A colony with laying workers shows characteristic signs, such as multiple eggs in a single cell, or eggs laid on the sides or off-center, unlike the queen who lays one egg precisely at the cell’s bottom. The presence of drone brood in smaller worker-sized cells, often with raised or “bullet-shaped” cappings, indicates laying workers. Such a colony, producing only drones and no new worker bees, faces population decline and is unlikely to survive long-term without intervention.