HAPLODIPLOIDY

Most animals inherit half their genes from their mother and half from their father. But in ants, bees, wasps and thrips, it’s not so simple. Males develop from unfertilised eggs, females from fertilised ones. The result is that sisters share three quarters of their genes, but mothers and offspring share only half. It may be no coincidence that such haplodiploid creatures tend to be highly social, with females sacrificing their own reproduction in favour of working together to raise more sisters.

Sisters are doing it for themselves.