Relatedness, Conflict, and the Evolution of Eusociality
The worker-assisted birthrate b and the probability of staying q are allowed to vary, while other parameters are as in Figure 4 of Nowak et al.  (m = 3, b0 = 0.5, d0 = 0.1, d = 0.01, α = 0.1, η = 0.01). Filled circles show values of relatedness r and worker-assisted queen birthrate b that select for eusociality (for at least one value of q) if the decision is made by offspring (Equation 2). Reducing relatedness makes eusociality harder to evolve (requires higher b). When the decision is made by genes acting in mothers (Equation 3), eusociality evolves under much broader conditions (open and filled circles), and lowering relatedness make eusociality easier to evolve. The open circles represent the zone of potential conflict, in which mothers but not offspring favor eusociality. The data used to make this figure can be found in S1 Dataset.