Speed of fixation for the virginity mutation when male mating capacity varies. The number of generations required for the recessive mutant allele for fertilization rate of n = 0 ("virginity mutation") to spread so that 99% of all females are infected and homozygous for the mutant (Inn), when the number of females a male is capable of inseminating varies from 1 to 20 females. Calculations were done using the simulation model (additional file 1) with the following conditions: mutant sex ratio allele has a fertilization rate of n = 0 in a population with a wild type fertilization rate of x = 0.5. In generation 1 a PI-Wolbachia infection is entered in the population in 1% of the females, while at the same time the mutant sex ratio is entered in 1% of the males. The PI-Wolbachia does not have any effect on the offspring production of the infected females (ω = 1) and has a transmission efficiency (α) of 95%.