σc/σr ratio —
Species count 1
Phase —
Generation 0
σ_c < σ_r: branching point
σ_c > σ_r: ESS (no branching)
White dots = populations
σ_c > σ_r: ESS (no branching)
White dots = populations
f(y,x) = invasion fitness | Branching point: ESS unstable, convergent stable