The evolution of self-fertilization in density-regulated populations

Area of Science:

• Evolutionary biology
• Population genetics
• Ecology

Background:

• The evolution of self-fertilization (selfing) in hermaphroditic organisms is a complex process.
• Previous studies often focused on extreme outcomes: complete selfing or complete outcrossing.
• Understanding the demographic factors influencing intermediate selfing rates remains crucial.

Purpose of the Study:

• To investigate the demographic conditions that promote intermediate selfing rates in hermaphrodites.
• To analyze the impact of density regulation and environmental variability on the evolution of selfing.
• To explore the interplay between inbreeding depression, outcrossing costs, and population dynamics.

Main Methods:

• Development of a demographic model incorporating Ricker-type density regulation.
• Assumptions included differential survival and competitive abilities of inbred versus outbred individuals.
• Analysis across three scenarios: stable, deterministically varying, and stochastically fluctuating population densities.

Main Results:

• Intermediate selfing rates can evolve even under stable demographic conditions.
• The nature of competitive interactions between inbred and outbred individuals significantly influences evolutionary outcomes.
• Both deterministic and stochastic density fluctuations can lead to the evolutionary stabilization of intermediate selfing rates.

Conclusions:

• Density regulation is a significant factor in shaping the evolution of selfing rates.
• Environmental variability can promote intermediate selfing, broadening our understanding beyond simple stable models.
• This study provides novel insights into the detailed effects of density regulation on the evolution of selfing.