Inclusive fitness from multitype branching processes

Area of Science:

• Evolutionary biology
• Theoretical ecology
• Population genetics

Background:

• Social behaviors impact an individual's neighbors' success.
• Mutant genes can alter an individual's competitive ability and influence reproductive success.

Purpose of the Study:

• To investigate genetic models for social behavior evolution.
• To clarify the definition and application of inclusive fitness in stochastic environments.
• To link inclusive fitness to the probability of mutant allele extinction.

Main Methods:

• Utilizing multitype branching processes.
• Applying approximations for rare mutant alleles and selection strength.
• Formulating statements on mutant extinction probability using inclusive fitness.

Main Results:

• Standard results for constant population sizes were recovered.
• Inclusive fitness was shown to predict short-term mutant fate under demographic fluctuations.
• A connection was established between inclusive fitness and stochastic social evolution.

Conclusions:

• Inclusive fitness is a valuable tool for understanding social evolution, even with random demographic changes.
• The study clarifies previous confusion regarding inclusive fitness in fluctuating populations.
• Provides a robust framework for analyzing the evolutionary dynamics of social traits.