Host-Parasite Coevolution: Red Queen Dynamics

Matching-allele model: a parasite infects a host when their alleles match. Frequency-dependent selection drives perpetual cycling — no equilibrium, just endless arms race. As in Lewis Carroll: "It takes all the running you can do, to keep in the same place."

Allele Frequencies

Host A1Para A1

Generation: 0

Host A1 freq: 0.50

Para A1 freq: 0.50

Phase: coexisting

Red Queen prediction: allele frequencies cycle perpetually. Period depends on mutation rate and selection strength. Sexual reproduction accelerates adaptation.

Selection s 0.30 Mutation μ 0.010 n alleles 2 Pop size 500