Stability of A Coevolving Host-parasite System Peaks at Intermediate Productivity

Area of Science:

• Ecology
• Evolutionary Biology
• Microbial Ecology

Background:

• Habitat productivity influences the stability of consumer-resource systems via ecological and evolutionary processes.
• Coevolving systems may exhibit varying stability based on resource availability, impacting population dynamics and species survival.

Purpose of the Study:

• To investigate how resource availability affects the stability of coevolving consumer-resource systems.
• To determine the relationship between resource levels, coevolutionary dynamics, and population stability in a model system.

Main Methods:

• Conducted an experimental evolution study using a bacterium-phage model system (Pseudomonas fluorescens and SBW25Φ2).
• Manipulated resource availability to assess its impact on population dynamics, extinction events, and coevolutionary rates.

Main Results:

• The bacterium-phage system demonstrated the highest stability at intermediate resource supply, characterized by fewer extinctions and reduced population fluctuations.
• The rate of coevolution between bacterial resistance and phage infectivity correlated positively with the magnitude of population fluctuations.
• Escalatory coevolutionary 'arms races' in resource-rich conditions were linked to increased population instability and extinction risk.

Conclusions:

• Environment-dependent coevolutionary dynamics play a critical role in the stability of consumer-resource systems.
• Understanding contemporaneous evolutionary dynamics is essential for predicting ecosystem stability, especially under changing environmental conditions.
• Intermediate resource availability appears optimal for maintaining stable ecological interactions and preventing extinctions driven by rapid coevolution.