Evolutionary suicide as a consequence of runaway selection for greater aggregation tendency

Area of Science:

• Ecology
• Evolutionary Biology
• Mathematical Modeling

Background:

• Aggregation is common in nature, offering benefits but incurring costs like competition.
• The Allee effect, where population density affects reproductive success, is hypothesized to drive aggregation evolution.
• Understanding aggregation dynamics is key to explaining population stability and evolutionary strategies.

Purpose of the Study:

• To investigate the evolution of aggregation behavior using a mathematical model integrating population dynamics and evolution.
• To determine if the Allee effect alone is sufficient for aggregation to evolve as an evolutionarily stable strategy.
• To explore the interplay between aggregation tendency, competition, and population-level feedback.

Main Methods:

• Developed a mathematical model combining population dynamics and evolutionary principles.
• Simulated scenarios with individuals benefiting synergistically from aggregation but facing scramble competition.
• Analyzed the evolution of aggregation tendency as a heritable trait.

Main Results:

• Aggregation can stabilize population dynamics but may reduce overall population growth.
• The Allee effect alone is insufficient for the evolution of aggregative behavior as an evolutionarily stable strategy.
• Weak local competition can paradoxically hinder aggregation, potentially leading to evolutionary suicide due to high population densities.

Conclusions:

• Aggregation evolution requires more than just the Allee effect; factors like inter-patch dispersal and group size limitation are important.
• High population densities resulting from low competition can make aggregation detrimental.
• Further research should incorporate spatial dynamics and group size regulation to understand stable aggregation.