the evolution of autosomal suppressors of sexratio drive in drosophila simulans sexratio drive which results in males siring femalebiased progeny has been reported in several drosophila species including d simulans it is caused by xlinked drivers that prevent the production of ybearing sperm in natural populations of d simulans the drivers are usually cryptic because their spread has elicited the evolution of drive suppressors we investigated autosomal suppression in flies from madagascar runion and kenya autosomal suppressors were found in all three places indicating that they are a regular component of drive suppression over this geographic area where strong ylinked suppressors also occur these suppressors were suspected of being polymorphic in madagascar and runion and proved to be polymorphic in kenya we developed a model simulating the evolution of neutral autosomal suppressors in order to explore the effects of the number of suppressor genes their relative strength and the cooccurrence of ylinked suppressors the most interesting prediction of the model is that when suppression is multigenic suppressor loci can remain polymorphic despite the absence of balancing selection if an equal sexratio is restored in the population before the suppressor alleles become fixed at all loci the model also emphasises the importance of the sterility of distorters sons in suppressor dynamics