Fig. 2.

Direct fitness benefits facilitate invasion of male-killers by lowering or removing the critical resource reallocation efficiency. Behavior of the critical resource reallocation efficiency, β ^crit, in dependence of the relative fecundity of infected females, F _MK, and the viability of males under MK, v, for F _MK < 1 (a) and F _MK > 1 (b). β ^crit disappears if F _MK t _MK > 1. t _MK = 0.95