Table 1 Model parameters and their values

P_tⁱ

Performance for animal i at time t

C_tⁱ

Pathogen number in animal i at time t

R_tⁱ

Immune response in animal i at time t

I_t

Number of infected animals in the population at time t

P_t

Population performance at time t

ΔE_P

Incremental effectiveness for P_t over the T period

ΔE_I

Incremental effectiveness for I_t over the T period

N

Population size

30

T

Time duration

300

C_min

Pathogen number necessary for infection

10

C^Max

Maximum number of pathogens

500

P^Max

Maximum performance

100

γ

Per-capita pathogen growth rate

0.5

β

Transmission rate

0.1; 0.5

μ

Maximum per-capita pathogen killing rate

0.25; 1.0

ω

Maximum performance loss per pathogen

0.1; 0.2

cⁱ_ρ

Marginal costs of resistance

U [0, 0.1]; U [0.1, 0.2]; U [0.2, 0.5]

cⁱ_λ

Marginal costs of tolerance

U [0, 0.1]; U [0.1, 0.2]; U [0.2, 0.5]

ρⁱ

Extra investment in resistance

U [0, 1]; U [0,0.5]; U [0.9, 1]

λⁱ

Extra investment in tolerance

U [0, 1]; U [0, 0.5]; U [0.9, 1]

hⁱ

Rate of increase for the immune index

U [0, 0.001]; U [0, 0.01]; U [0, 0.1]