brood (their sisters, in particular). Under theories of inclusive fitness, it is potentially beneficial for workers to help their mother produce a second brood if that brood is primarily female. However, H. rubicundus does not show female bias in the second brood, with values only ranging to a maximum of 40% female. Furthermore, the one study providing empirical data for H. rubicundus shows that a typical worker contributes to the production of 0.9 sisters and 0.8 brothers, far below the threshold for inclusive fitness effects to favor helping, but above the threshold at which their mother benefits directly; as such, this species provides evidence that kin selection effects would not apply to this species, and instead suggests that mothers manipulate some of their daughters into acting as workers because of direct gains to maternal fitness, even though these manipulated daughters have lower fitness than they could have had if they had been gynes. References External links rubicundus Hymenoptera of North America Insects described in 1791 Taxa named by Johann Ludwig Christ