Density dependent selection incorporating intraspecific competition 1. A haploid model.

Area of Science:

• Population Genetics
• Ecological Modeling

Background:

• Traditional haploid models often assume simple density dependence.
• Intraspecific competition's role in maintaining genetic variation is complex and requires nuanced modeling.

Purpose of the Study:

• To develop and analyze a haploid population model incorporating density-dependent intraspecific competition.
• To investigate how genotype-specific competition affects population dynamics and allele stability.

Main Methods:

• Introduction of a haploid model with density-dependent intraspecific competition.
• Mathematical analysis of genotypic fitness as a function of genotype frequencies and competition coefficients.
• Examination of equilibrium stability under varying intergenotypic interaction strengths.

Main Results:

• A stable interior equilibrium allowing coexistence of all alleles is possible when competition is genotype-dependent.
• Selective advantage depends on a balance between carrying capacity and competitive pressure.
• Fixation of the highest-carrying-capacity genotype is not always stable if its competitive effect is weak.

Conclusions:

• Genotype-specific intraspecific competition can promote stable genetic polymorphism in haploid populations.
• The model provides insights into the conditions required for maintaining genetic diversity beyond simple density regulation.
• Results can be extended to models of discrete-time interspecific competition.