The evolution of bequeathal in stable habitats

Area of Science:

• Evolutionary biology
• Behavioral ecology
• Population genetics

Background:

• Parental care and offspring dispersal are key life-history traits.
• Bequeathal, where offspring inherit natal sites, is observed but poorly understood theoretically.
• Existing empirical studies lack a robust evolutionary framework.

Purpose of the Study:

• To develop a mathematical model exploring the evolutionary conditions favoring bequeathal.
• To identify key ecological and demographic factors influencing the evolution of natal site inheritance.
• To determine when bequeathal is an Evolutionarily Stable Strategy (ESS) and when it can invade.

Main Methods:

• A simple mathematical model was constructed.
• Simulations considered stable environments with global and local dispersal.
• Model parameters included adult competitive advantage, mortality rates, and environmental saturation.

Main Results:

• Natural selection favors bequeathal under high adult competitiveness, high baseline mortality, unsaturated environments, and high juvenile dispersal mortality.
• Bequeathal often fails to evolve due to high adult fitness costs outweighing inclusive fitness gains.
• Situations exist where bequeathal is an ESS but cannot invade, highlighting complex evolutionary dynamics.

Conclusions:

• Bequeathal evolution is contingent on a balance between adult advantages and offspring dispersal costs.
• Facultative bequeathal in nature may be influenced by factors not yet modeled, such as breeding season timing.
• Further theoretical and empirical work is needed to fully understand the evolution of natal site inheritance.