Why don't male bees have a father but have a grandfather?

Male bees (drones) do not have fathers but have grandfathers due to haplodiploidy. Drones develop from unfertilized eggs and are haploid, inheriting only one set of chromosomes from their mother. Since no fertilization occurs, they lack a father. However, their mother is diploid, so they inherit genes from their maternal grandfather, making them his genetic descendants.