Figure 7. Comparing the effect of single mating (n = 1) and double mating (n = 2) on the evolution of worker sterility.
Whether or not single or double mating favors the evolution of worker sterility depends on the functions pz and rz. The function pz specifies the fraction of male offspring that come from the queen if a fraction, z, of all workers in the colony is non-reproductive. The function rz specifies the reproductive rate (or efficiency) of the colony if a fraction, z, of all workers in the colony is non-reproductive. We consider a recessive mutant allele, a, for worker sterility. (A, B) For these parameter choices, the mutant allele causing worker sterility can invade for double mating but not for single mating. (C, D) For these parameter choices, the mutant allele causing worker sterility is evolutionarily stable for double mating but not for single mating.