The sex determination in the honey bees is mainly understood by the fertilisation and non-fertilisation of eggs. Johann Dzierzon in 1845 discovered this type of the sex determination.
In haplo-diploid system, the male progeny develops from the unfertilised eggs. The eggs are haploid and carry only one set of the chromosomes. These are known as drones or male honey bees. The queens and worker bees develop from the fertilised honey bee eggs, which have two sets of chromosomes and act as diploid eggs.