More extinction driven by the Red Queen in smaller habitats

Area of Science:

• Evolutionary biology
• Ecology
• Microbiology

Background:

• Antagonistic coevolutionary interactions drive populations to adapt or face extinction.
• Habitat size can influence evolutionary potential and the speed of coevolutionary processes.
• Bacterium-virus systems often exhibit asymmetric evolutionary speeds, with viruses at a disadvantage.

Purpose of the Study:

• To investigate the effect of declining habitat size on antagonistic coevolution.
• To determine if smaller habitats increase the likelihood of extinction in coevolving populations.
• To explore implications for biodiversity and biocontrol.

Main Methods:

• Experimental evolution using the bacterium Pseudomonas fluorescens SBW25 and its lytic phage SBW25Φ2.
• Manipulation of habitat size to simulate declining environments.
• Assessment of viral extinction rates, infectivity, and bacterial population densities.

Main Results:

• Smaller habitats significantly increased the likelihood of viral extinction.
• Persisting viral populations from smaller habitats exhibited reduced infectivity.
• Bacterial populations in smaller habitats showed higher densities.

Conclusions:

• Declining habitat size exacerbates extinction risk in coevolutionary interactions, particularly in bacterium-virus systems.
• Reduced habitat size can lead to decreased viral infectivity and increased host population density.
• Findings suggest that coevolutionary processes intensify the impact of habitat loss on biodiversity and inform biocontrol strategies.