Fig. 2

Prediction of the relationship between body fatness and mortality with the different parameter values (modified from Speakman (2018) [19]). The formula of the disease-predation dual-intervention point model is \(a \times {e}^{-bF}+h+c \times {e}^{gF}+j\) (F stands for body fatness; a, b, c, e, h, and j are parameters). For red line, a = 1.0, b = 0.3, c = 0.123, g = 0.2, j = h = 0; For blue line, a = 0.53, b = 0.07, c = 0.123, g = 0.117, h = j = 0. Units for mortality and fatness are arbitrary