Ecological histories govern social exploitation by microorganisms

Area of Science:

• Evolutionary biology
• Microbial ecology
• Behavioral ecology

Background:

• Exploitation is a common social interaction, influenced by ecological context.
• The role of ecological history in shaping exploitation phenotypes remains understudied.

Purpose of the Study:

• To investigate the effects of ecological history, specifically prior resource levels, on exploitation phenotypes in the bacterium Myxococcus xanthus.
• To determine how resource history influences social fitness and the occurrence of cheating during cooperative development.

Main Methods:

• Experiments with Myxococcus xanthus involving different genotypes and resource level histories.
• Manipulation of resource levels experienced by interacting cooperators and cheaters.
• Analysis of developmental spore production and relative fitness advantages.

Main Results:

• Prior resource levels significantly regulated social fitness and the occurrence of cheating.
• Cheating advantages were reduced or absent when one or both interacting partners experienced low-resource growth.
• Low-resource growth eliminated exploitation in some pairwise interactions of cooperative natural isolates.

Conclusions:

• Ecological history, particularly resource availability history, plays a crucial role in regulating exploitation in bacterial social interactions.
• Findings contrast with previous studies suggesting concurrent resource levels are key, highlighting the importance of historical resource variation in natural contexts.