Coevolutionary interactions between a haploid species and a diploid species

Area of Science:

• Evolutionary Biology
• Population Genetics
• Theoretical Ecology

Background:

• Coevolutionary dynamics are complex, especially involving populations with different ploidies.
• Understanding these interactions is crucial for predicting evolutionary trajectories and biodiversity patterns.

Purpose of the Study:

• To develop and analyze a general mathematical model for coevolution between haploid and diploid populations.
• To determine the equilibrium states and outcomes of these complex interspecific interactions.
• To explore the implications for the geographic mosaic theory of coevolution.

Main Methods:

• A general mathematical model was formulated for a haploid and a diploid population, each with two alleles at a single locus.
• Fitness functions were defined as linear dependencies on the genotype frequencies of the interacting species.
• A semi-symmetric model was constructed for further analytical exploration of outcomes.

Main Results:

• The model demonstrates that coevolution between haploid and diploid populations is significantly more complex than between two haploid populations.
• The analysis identified conditions allowing for the existence of two distinct polymorphic equilibria.
• Even a simplified semi-symmetric model exhibited a wide variety of potential coevolutionary outcomes.

Conclusions:

• The complex dynamics and multiple equilibria observed support the geographic mosaic theory.
• Local populations can evolve to divergent outcomes, creating a dynamic geographic mosaic through inter-population migration and interaction.