Fig 1.
Sensitivity of the mature age density to the internal stochasticity.
This figure illustrates the effect of the magnitude of noise on the mature age density under both r- and K-selection. The horizontal axis denotes the logarithmic scale of the age, and the vertical axis denotes the height of the mature age density function on the logarithmic scale. The solid line and the dashed line represent the mature age density functions under K-selection and r-selection, respectively. Both mature ages are biased to precocity depending on the magnitude of the noise; furthermore, we see that r-selection does not always accelerate maturity under internal stochasticity. The parameters of this simulation are b1 = 0.15, σ1 = 0.4,0.5,0.6, x = 0.01, x* = 1.5, ϕ(x*) = 10, and μ0 = 0.01.
Fig 2.
The K-strategy of the two-resource utilization model.
This figure shows the shape of adaptive utilization under K-selection with respect to the ratio of the strength in the intraspecific competition κ. As the ratio increases, the adaptive strategy shifts to R1-specialists, generalists, and R2-specialists in turn. It is known that R2-specialists do not evolve in the absence of density effects [9]. The parameters are b1 = 0.15, b2 = 0.05, σ1 = 0.6, σ2 = 0.02, x = 0.01, x* = 1.5, ϕ(x*) = 10, and μ0 = 0.01.
Fig 3.
Differences in the intrinsic rate of the natural increase between both strategies.
The figure illustrates the values of IRNI in the r- and K-strategies. The horizontal axis denotes the ratio of strength in the intraspecific competition (κ), and the vertical axis denotes the IRNI. The solid line and the dashed line represent the IRNI of the K-strategy and r-strategy, respectively. The curves are given by Eqs (F.8), (F.9) and (F.15) at Text F in S1 File. The IRNI of the r-strategy is always greater than that of the others based on its definition. The domains of both the specialists and generalists represent the K-strategy because the r-strategy is independent of intraspecific competition. The parameters used are the same as those used for Fig 2.
Fig 4.
The potential basic reproductive numbers in the r- and K-strategies.
This figure illustrates for both strategies in the absence of density effects. The horizontal axis shows the ratio of the strength in the intraspecific competition (κ), and the vertical axis represents
under Γt = 0. The solid and the dashed lines represent the same entities as those in Fig 3, and the parameters used are also the same. It is shown that the K-strategy of
is not always higher than the other. Therefore, the basic reproductive number of the K-strategy potentially depends on the ratio of the strength in the intraspecific competition.
Fig 5.
Sizes of the carrying capacity in both r/K strategies.
The horizontal axis represents the ratio of the strength in the intraspecific competition (κ), and the vertical axis represents the size of the carrying capacity . The solid and the dashed lines represent the same entities as those in Fig 3, and the parameters used are also the same. Each vertical dashed line represents the boundary between the specialists and the generalists. This figure shows that the K-strategy always has greater carrying capacity than the other strategies, as demonstrated by Eq (32).