Density Dependence Triggers Runaway Selection of Reduced Senescence
Figure 4
Simulated Adult Population in Presence of a Low Rate of Extrinsic Adult Mortality
(A) Evolution over time in x (population mean and minimum), showing progressively later onset of vitality loss until most have negligible or zero senescence.
(B) Concurrent reduction in μ0 (mean and minimum) until some have zero aging; the dashed line is the optimum μ0* = 0.017, determined by the Marginal Value Theorem (see Appendix B of Text S1).
(C) Adult population (upper black line) and intrinsic immortals (lower red); the dashed line is the carrying capacity K.
(D) Adult age (mean and maximum) showing extended span for intrinsic immortals. Input parameter values: αb = αd = 0.5; random mutational increments of up to ±0.01 in x and μ0; δt = 0.01; B0 = 10, D0 = 0.3; ω0 = B0μ0/(D0 + μ0); g = 0.001; and b0(x) = ω0(1 + 0.2xe−1/x).