Final answer:
Eusociality has evolved multiple times in ants, bees, and wasps due to kin selection. Sterile worker insects care for the reproductive individuals (queens) who indirectly pass on their genes. This behavior benefits the worker's inclusive fitness.
Step-by-step explanation:
Eusociality has evolved multiple times within the hymenoptera (ants, bees, and wasps) due to kin selection. In eusocial colonies, sterile worker insects care for the reproductive individuals (queens) who pass on their genes indirectly. Even though the workers cannot reproduce themselves, they share a significant amount of genetic material with the queen, making it beneficial for them to ensure the survival and reproduction of the queen. This behavior increases the worker's inclusive fitness, which is the combination of their own direct fitness and the fitness gained through relatives sharing genes with them.