This unusual situation where females may have greater fitness when they help rear siblings rather than producing offspring is often invoked to explain the multiple independent evolutions of eusociality -LRB- occurring some NUMBER@1 separate times -RRB- within the haplodiploid group Hymenoptera -- ants , bees and wasps .

This unusual situation where females may have greater fitness when they help rear siblings rather than producing offspring is often used to explain that eusociality evolved several times , independently in the haplodiploid group Hymenoptera -- ants , bees and wasps .
