Dual-stressor selection alters eco-evolutionary dynamics in experimental communities

Area of Science:

• Eco-evolutionary dynamics
• Evolutionary biology
• Ecology
• Microbial evolution

Background:

• Rapid evolution is crucial for ecological processes, including community assembly and ecosystem stability.
• Evolutionary change is driven by selection on genetic variation, influenced by constraints like trade-offs.
• Environmental stressors can impact reproductive output and influence evolutionary trajectories.

Purpose of the Study:

• To investigate how multiple environmental stressors affect the link between rapid evolution and ecological change.
• To understand the consequences of multistressor selection on eco-evolutionary dynamics and predictability.

Main Methods:

• Experimental evolution using the bacterium Pseudomonas fluorescens and its predator Tetrahymena thermophila.
• Application of two stressors: predation and sublethal antibiotic concentrations.
• Tracking molecular evolution of bacterial populations over time.

Main Results:

• The combination of predation and antibiotics delayed the evolution of anti-predator defense and antibiotic resistance compared to single stressors.
• Rapid defense evolution stabilizes predator-prey dynamics, but this link is weaker under multi-stressor conditions due to slower evolution.
• Multistressor selection favored mutations in different genes, altering the molecular evolutionary pathways.

Conclusions:

• Multiple environmental stressors can significantly alter eco-evolutionary dynamics by slowing down adaptive evolution.
• The predictability of ecological change driven by rapid evolution is reduced under multi-stressor scenarios.
• Understanding multistressor effects is essential for predicting future ecological and evolutionary trajectories.