How does haplodiploidy affect genetic relatedness among ant, bee, and wasp sisters?

In the insect order Hymenoptera, haplodiploidy is a system of sex determination where males develop from unfertilized, haploid eggs, while females develop from fertilized, diploid eggs.123

This system significantly influences genetic relatedness among sisters in ant, bee, and wasp colonies:

• Paternal contribution: Because fathers are haploid, they possess only one set of genes to pass on. Consequently, all sperm produced by a single father are genetically identical.2
• Maternal contribution: Diploid mothers produce a variety of genetically different eggs, sharing on average 50 percent of their genes with each daughter.24
• Resulting relatedness: Because sisters receive 100 percent of their father's genes and 50 percent of their mother's genes (on average), they share 75 percent of their genes with one another.24

This high degree of relatedness—compared to the 50 percent they would share with their own potential offspring—suggests that female workers may increase their inclusive fitness by helping their mother produce more sisters rather than reproducing themselves. However, this effect can be diluted if a queen mates with multiple males, and haplodiploidy is considered a predisposing factor rather than the sole cause of eusociality.24