Host-parasite interactions and the evolution of nonrandom mating.

Area of Science:

• Evolutionary biology
• Immunogenetics
• Population genetics

Background:

• Nonrandom mating patterns are observed in species related to immune alleles.
• A hypothesis suggests nonrandom mating increases offspring parasite resistance.

Purpose of the Study:

• Investigate the hypothesis that nonrandom mating enhances parasite resistance.
• Generalize previous models by examining evolutionarily stable strategies, host-parasite ploidy, maternal transmission, and multiple alleles.

Main Methods:

• Analysis of evolutionarily stable strategies (ESS) for mating modifiers.
• Modeling coevolutionary dynamics of haploid and diploid hosts and parasites.
• Incorporation of maternal parasite transmission and multi-allele interactions.

Main Results:

• ESS mating rates are typically zero or one, except in MHC-like systems where intermediate disassortative mating evolves.
• Haploid hosts evolve complete disassortative mating; diploid hosts can evolve either assortative or disassortative mating.
• Maternal transmission and increased alleles at the interaction locus promote higher rates of disassortative mating.

Conclusions:

• Nonrandom mating, particularly disassortative mating, can evolve to increase parasite resistance.
• Host ploidy significantly influences mating evolution, while parasite ploidy has less impact.
• Specific conditions, like MHC-like interactions and maternal transmission, favor intermediate disassortative mating.