Red Queen — Host-Parasite Coevolution

Red Queen Coevolution

Matching alleles model: hosts resist when alleles don't match parasites. Frequency-dependent selection drives perpetual cycling — the Red Queen hypothesis.

Host pop size: 500 Parasite pop size: 500 Infection cost s: 0.3 Resistance cost c: 0.1 Alleles per locus: 4 Mutation rate: 0.01 Sex (recomb): 0.5

Red Queen hypothesis:
Sex evolves to generate novel allele combinations faster than asexual reproduction, keeping ahead of parasites.

Matching alleles: parasite succeeds if host&parasite share alleles → negative frequency-dependent selection