Simulated, fitted, and normalized distributions of incubation periods for birth-death dynamics on a complete graph of nodes. Unless stated otherwise, each simulation used an invader fitness of , measured times till complete takeover (), and started from an initial dose of 1 invader. Runs where the dosage was not smaller than the truncation point were rejected. The blue curves indicate noncentral lognormals fitted via the method of moments. (a) Heterogeneous fitness of invader. Every run used a different selected from a Gamma distribution with a shape parameter of 10. (b) Heterogeneity of host response. Instead of waiting until all residents had been replaced by invaders, every run used a different truncation point uniformly selected from . (c) Heterogeneity of dosage. Every run had a different starting population drawn from a Poisson of mean 10 and a shift of 1. (d) Heterogeneity of invader fitness, host response, and dosage. Every run used an drawn from Gamma(10), a truncation point drawn from Uniform(0,1), and a dosage drawn from Poisson(10)+1.