Each virgin mates with seven or more drones, and thus the colony is made up of seven or more sub-families. In most sexually reproducing organisms, sex determination is governed by a sex chromosome. In honey bees, however, sex is determined by a single gene. This gene has many variants or alleles, maybe as many as 18. One should feel lucky, however, to maintain 10 or so in a breeding population.
Drones are haploid and have one allele.
However, if two of the same allele come together, a diploid male results. We never see diploid drones in the hive because when only a few hours old, they are cannibalized by the workers. As the number of sex alleles decreases, the more likely it is that two of the same allele will come together, increasing the number of diploid drones. As the percentage of diploid drones produced increases, so does the spottiness of the brood. There is an obvious impact on a colony's productivity, therefore, when some well-intentioned bee breeder reduces the number of sex alleles in a queen.