Galeopsomyia fausta (Hymenoptera: Eulophidae) is a thelytokous parasitic wasp attacking the citrus leafminer,Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae). To improve the performance of that wasp as a natural enemy, the nature of its uniparental reproduction was studied. It was found that the production of males can be induced by antibiotic treatments, but attempts to establish a biparentalG. fausta line have failed. The reproductive barrier between antibiotic-induced males and conspecific females appears to be the non-receptivity of females. The results imply involvement of microorganisms in the thelytokous reproduction ofG. fausta, but noWolbachia was detected in polymerase chain reaction.