Fig. 1.

Polygyny intensity and reproductive skew as a function of male rival resource inequality, rival resource importance, and mating system norms using the generalized polygyny threshold model introduced by Oh et al. (19). Male rival resource inequality, R, is measured using the Gini coefficient and ranges ∈(0.12, 0.64). Rival resource importance, μ, is measured using the fitness elasticity of rival resources and ranges ∈(0.15, 0.95). Nonrival resources, G, are held constant with a Gini coefficient of 0.12. Nonrival resource importance, γ, is measured using the fitness elasticity of nonrival resources and is given by the equation γ = 1 − μ to ensure constant returns to scale. For further methodological and mathematical details, SI Appendix, S3. (A) Male polygyny (e.g., percentage of married men with more than one wife) and female polygyny (e.g., percentage of women with cowives) as a function of male rival resource inequality, rival resource importance to fitness, and mating system norms. (B) Reproductive skew, M, as a function of male rival resource inequality, rival resource importance to fitness, and mating system norms.