Behavioral Interactions between Bacterivorous Nematodes and Predatory Bacteria in a Synthetic Community

Area of Science:

• Microbial ecology
• Predator-prey dynamics
• Behavioral ecology

Background:

• Apex predators influence lower trophic levels in metazoans.
• Microbial communities are ecologically important, yet predatory microbial interactions are understudied.
• Trophic interactions in microbial food webs require further investigation.

Purpose of the Study:

• To establish a three-level microbial food chain.
• To investigate behavioral interactions between predatory nematode Caenorhabditis elegans and predatory bacterium Myxococcus xanthus.
• To test predator responses with two basal prey bacteria: Escherichia coli and Flavobacterium johnsoniae.

Main Methods:

• Co-culturing of C. elegans, M. xanthus, E. coli, and F. johnsoniae.
• Observing and quantifying C. elegans predatory behavior towards M. xanthus and basal prey.
• Measuring M. xanthus swarming rates in response to C. elegans presence and density.

Main Results:

• C. elegans largely avoided M. xanthus, preferring E. coli and F. johnsoniae.
• M. xanthus repelled C. elegans from attractive prey patches, mimicking pathogen effects.
• M. xanthus increased swarming rates in response to C. elegans, dependent on prey and worm density.

Conclusions:

• M. xanthus is an unattractive prey for C. elegans and is avoided when alternative prey exist.
• Nematode and bacterial predators mutually influence each other's predatory behaviors.
• These interactions have significant implications for coevolution within complex microbial food webs.