Why do worker ants and bees often give up reproduction to help a queen?

Worker ants and bees often forgo their own reproduction to assist a queen due to a combination of environmental constraints and the evolutionary benefits of kin selection.21

Evolutionary Drivers

• Constraints on Independent Breeding: Workers often face significant barriers to reproducing on their own, such as a shortage of suitable nesting sites, limited food resources, high predation rates, or short breeding seasons. In these environments, the likelihood of successfully raising offspring independently is low, making it more advantageous to remain in the natal colony.213
• Inclusive Fitness: Through the theory of inclusive fitness, individuals can pass on their genes not only by producing their own offspring but also by helping close relatives survive and reproduce. By supporting the queen—who is typically their mother—workers ensure the propagation of shared genes.231
• Genetic Relatedness: In many Hymenoptera (the order including ants, bees, and wasps), a genetic system called haplodiploidy can result in sisters sharing a high percentage of their genes. This high relatedness means that, in some cases, a worker may gain more genetic representation in the next generation by helping the queen produce more sisters than by producing her own offspring.2

Once a colony is established, selection strongly favors traits that improve overall colony efficiency, leading to the specialized division of labor seen in eusocial insects.21