Figure 5. Evolutionarily stable sex allocation strategies when sex- and stage-specific mortality rates vary.

Effect of male and female gametocyte mortality and male gamete mortality on the ES gametocyte sex ratio (z*), for a clonal population, when the number of gametes produced per male gametocyte (χ) is 2 (this fecundity has been estimated for this system by other studies; see ref. [19]). Figures S1, S2, S3 show similar patterns to Figure 5A for χ = 1; 4; 8, respectively. (A) For each plot within the panel, z* varies with male gamete mortality rate (δ_M). The coloured lines represent different gametocyte group sizes (q): 2 (grey), 5 (blue), 10 (red), 20 (green) and ∞ (yellow). Each plot depicts different parameter combinations of male gametocyte (d_M = 0.1; 0.5; 0.9) and female mortality rate (d_F = 0.1; 0.5; 0.9), with d_M increasing left to right and d_F increasing bottom to top. (B) Cartoon summarizing the effects observed in Figures 5A and S1, S2, S3. The set of possible values for z* is strongly influenced by q. The number of gametes of each sex reaching the mating pool (which depends on the mortality parameters and on χ) influences z* within the constraints determined by q. Within each plot, the effects of δ_M and q on z* can be clearly observed: the magnitude of sex ratio change increases with q and z* increases to compensate for higher δ_M. The effects of d_M and d_F can be observed by comparing the points where the lines cross the y axes (i.e. δ_M = 0) across the plots: z* increases along rows with increasing d_M and decreases up the columns with increasing d_F. The effect of χ on z* can be observed by comparing plots that are in the same position in different figures: sex ratio becomes more female biased as χ increases.