The effect of a competitor on a model adaptive radiation

Area of Science:

• Evolutionary Ecology
• Microbial Ecology
• Speciation Research

Background:

• Adaptive radiation, the diversification of a lineage into different ecological niches, is a key process in evolution.
• Understanding the ecological factors that influence adaptive radiation is crucial for evolutionary biology.
• Competition is hypothesized to limit the diversification of a focal lineage.

Purpose of the Study:

• To experimentally test if interspecific competition limits microbial adaptive radiation.
• To investigate the effects of a competitor on the diversification of Pseudomonas fluorescens.
• To determine how environmental context (spatial heterogeneity) modifies the impact of competition on diversification.

Main Methods:

• A model microbial adaptive radiation system using Pseudomonas fluorescens.
• Experimental manipulation of the presence or absence of a competitor, Pseudomonas putida.
• Comparison of diversification dynamics in spatially homogeneous and heterogeneous environments.

Main Results:

• In heterogeneous environments, P. putida had minimal impact on P. fluorescens population size and no effect on diversification.
• In homogeneous environments, P. putida significantly reduced P. fluorescens population size and accelerated early diversification.
• P. putida altered P. fluorescens community structure by suppressing common variants and facilitating rare morphs in homogeneous environments.

Conclusions:

• Interspecific competition can have complex, non-limiting effects on adaptive radiation.
• Environmental context critically influences the outcome of competition during diversification.
• Current evolutionary theory may not fully capture the nuanced impacts of competition on adaptive radiations.