Phylogenetic perspectives on genetic systems and reproductive modes of mites. Pattern of reproduction in insects. Evolutionary flexibility through haploid males or how chance favours the prepared genome. Endosymbiotic sex ratio distorters in insects and mites. Evolution of sex determination and sex ratio within the mite cohort tarsonemina. Sex allocation ratio selection in thysanoptera. Ecology and evolution of biased sex ratios in bank and ambroisa beetles. Evolution of sex ratio in aphids. Sex allocation in social insects: problems in prediction and estimation. Male parentage and sexual deception in the social hymenoptera. Sex ratio and virginity in haplodiploid insects. Sex ratio manipulation by parasitoid wasps. Sex determination and sex ratio patterns in parasitic hymenoptera. Sex ratio evolution in parasitic wasps. Sex allocation and pseudo-arrhenotoky in phytoseiid mites. Quantitative genetics applied to haplodiploid insects and mites.