Fig. 3

Emergence of virulent mutualists under competition. A An example epidemic trajectory for \(b=0.2\) displaying the proportions of the three disease states. B Epidemic trajectories for different degrees of competition with the younger, potentially reproductive, fraction of the population displayed. C Population growth rate, \(\frac{dN/dt}{N}\), over the course of the epidemic which quickly reaches a state of endemic equilibrium. D Comparison of initial, disease free, growth rates and final growth rates at endemic equilibrium. E Equivalent increase in birth rate resulting in the same growth rate increase for variable infection death rates among post-reproductive hosts. For strongly competitive populations the equivalent birth rate increase can reach 2%