Abstract: The sex determination mechanisms of insects are diverse and complex. In hymenopteran insects, males are haploid and females diploid. In this article, we reviewed the modes and molecular mechanisms of sex determination in hymenopteran insects. Six patterns for sex determination of hymenopteran insects have been reported, including the complementary sex determination (CSD), multiple-locus hypothesis (multiple-locus CSD, ml-CSD), genomic imprinting, maternal effects, endosymbionts inducing female parthenogenesis, and paternal genome elimination (PGE). Among them, CSD is a widely accepted model of sex determination in hymenopteran insects represented by honeybees. Sex determination of honeybees is controlled by the cascade of csd→fem→dsx.

Key words: Hymenoptera, sex determination, complementary sex determination, honeybee; diploid