Figure 1.

A hypothetical scheme of the life of a supercolony. In a young colony, relatedness between individuals is high as a result of the small number of founder queens. Relatedness decreases as the colony grows and expands. But even if relatedness between individuals who do not behave aggressively to each other drops to zero, relatedness to individuals who benefit from worker altruism remains above zero. Factors that increase relatedness between individuals in altruistic interactions include: limited dispersal of sexuals, context-specific discrimination and variation in kin structures over worker life-time.