In certain populations of the monogynous harvester ant Pogonomyrmex barbatus, there are two mitochondrial lineages (J1 and J2), each associated with particular alleles at nuclear loci.  Between-lineage matings result in the production of workers and within-lineage matings result in the production of reproductives (Helms Cahan S. et al. 2002. Proc. R. Soc. Lond. B 269: 1871-1877; Julian G. et al. 2002. PNAS U.S.A. 99: 8157-8160; Volny V. and Gordon D.M. 2002. PNAS 99: 6108-6111; Helms Cahan S. and Keller L. 2003 Nature 424: 306-309).  Males are haploid and are produced parthogenetically.  This system imposes constraints on colony establishment and reproduction because females must mate multiply in order to found colonies that can produce both workers and female reproductives.  A queen produces all of her offspring from sperm garnered at one nuptial flight.  The lineage ratio among males at the nuptial flight should influence the probability that a queen will successfully found a colony, e.g. a J1 queen will have a higher chance of founding a colony than a J2 queen if there are more J2 than J1 males.  The lineage ratio is highly asymmetrical at numerous sites in Southeastern Arizona.  We investigate the extent to which worker reproduction mediates the constraints imposed by the two-lineage system on colony founding success.  We find no evidence of worker produced males in P. barbatus, suggesting that workers do not reproduce or policing behavior prevents development of their offspring.  Our results are consistent with predictions that frequency dependent selection maintains the two lineages in natural populations.