Haplodiploidy
Lexikon
In the honey bee, the queen and the workers develop from fertilized, diploid eggs, while drones develop from unfertilized, haploid eggs.
In the honey bee, the queen and the workers develop from fertilized, diploid eggs, while drones develop from unfertilized, haploid eggs. A drone therefore has no father, only the genetic material of his mother. This form of sex determination is called haplodiploidy.
Whether the queen adds sperm when laying an egg depends on the cell size: she lays unfertilized eggs into the wide drone cells and fertilized eggs into the narrow worker cells. When forming his sperm, the drone needs no reduction division, so he passes on his genetic material unchanged, millions of times over.
The actual sex switch is a gene abbreviated csd. It occurs in a very large number of different versions. Only when an egg carries two different versions is the switch set to female. If a fertilized egg carries the same version twice, a diploid drone results, which the workers recognize as a larva and remove.
This produces the well-known sign of inbreeding: a patchy, sparse brood nest with many empty cells among the brood. Anyone who finds such a pattern should first think of parent animals that are too closely related, before suspecting a brood disease. Inbreeding is naturally prevented by queens visiting drone congregation areas far away.