How frequency-dependent selection affects population fitness, maladaptation and evolutionary rescue

Area of Science:

• Evolutionary biology
• Ecology
• Genetics

Background:

• Frequency-dependent (FD) selection is a key evolutionary process that maintains genetic variation and influences population fitness.
• While FD selection is studied across various biological disciplines, its implications for applied issues like conservation and evolutionary rescue are underexplored.
• Classical theory shows FD selection can increase or decrease population fitness, with relevance to population persistence and evolutionary rescue.

Purpose of the Study:

• To revisit the theory of FD selection and its consequences for population fitness.
• To develop a quantitative genetic model for evolutionary rescue in deteriorating environments under FD selection.
• To explore how FD selection impacts population persistence and evolutionary rescue in changing environments.

Main Methods:

• Review of classical single-locus models of population genetic change.
• Development of a quantitative genetic model for evolutionary rescue.
• Analysis of empirical literature supporting model assumptions.

Main Results:

• FD selection can promote population persistence when it aligns with frequency-independent selection from environmental conditions.
• In most environmental change scenarios, FD selection restricts a population's evolutionary adaptability.
• FD selection narrows the rate of environmental change that populations can tolerate evolutionarily.

Conclusions:

• FD selection has complex effects on population persistence and evolutionary rescue.
• Understanding the interplay between FD and frequency-independent selection is vital for predicting evolutionary rescue success.
• FD selection's impact on evolutionary responsiveness has significant implications for conservation and managing threatened populations under climate change.