A fertilized egg produces a female, while an unfertilized egg (haplodiploidy) produces a male. To fertilize the egg, at the time of laying, the queen uses the semen stored in the spermatheca. The type of diet she is subjected to determines whether the female will be a worker or a queen: future queens are fed only royal jelly, while workers are fed royal jelly only for the first three days of the larval stage, and then with a mixture of pollen and honey.