Table 1.

Description of parameters and variables. The variables for the polymorphic model (equations 12–13) are identical except for the addition of subscripts

Parameter/variable	Description
$\mathit{b}(\mathit{f}(\mathit{\beta }),\mathit{g},\mathit{v}(\mathit{\beta }))$	Host birth rate
d	Natural mortality rate
f(β)	Fecundity of infected hosts relative to uninfected hosts, which may be a function of transmission
g	Strength of mate choice
h	Strength of density‐dependent competition
m S(g)	Probability of accepting an uninfected mate
m I(g, v(β))	Probability of accepting an infected mate
p	Baseline per‐capita mating rate
r	Maximum reproduction rate per mating
v(β)	The impact of STI virulence on mate choice
R 0(g, β)	Basic reproductive ratio
S, I	Density of susceptible and infected hosts, respectively
N	Total density of hosts
[XY]	Sexual contact rate between hosts in the X and Y classes
[XY]b	Contribution to births from hosts in the X and Y classes in the polymorphic model
S ○	Sum over all susceptible hosts in the polymorphic model
I i○	Sum over all parasite types in hosts of type i in the polymorphic model
I ○j	Sum over all host types infected with parasites of type j in the polymorphic model
${\mathit{I}}_{\circ \circ }$	Sum over all infected hosts in the polymorphic model
$\mathit{\alpha }(\mathit{\beta })$	Mortality virulence, which may be a function of transmission
β	Transmission probability per sexual contact
γ	Recovery rate
ζ	Strength of host costs
η	Strength of transmission‐sterility virulence relationship
κ	Strength of transmission‐mortality virulence relationship
n h, n p	Number of host and parasite types, respectively, in the polymorphic model