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Using Coculture to Detect Chemically Mediated Interspecies Interactions
Published on: October 31, 2013
Novel cooperation experimentally evolved between species.
1Section of Integrative Biology, The University of Texas at Austin, Austin, Texas 78712, USA. wharcombe@oeb.harvard.edu
Evolution; International Journal of Organic Evolution
|January 27, 2010
Summary
This study shows that interspecific cooperation can evolve in the lab. It requires pre-existing reciprocation and benefits to be directed towards cooperative individuals, demonstrating a pathway for the evolution of cooperation between species.
Area of Science:
- Evolutionary biology
- Microbial ecology
- Behavioral ecology
Background:
- Cooperation is common in nature, yet its evolutionary origins, especially between species, remain poorly understood.
- Existing research primarily focuses on cooperation within a single species, often through kin selection.
- The experimental factors driving the evolution of cooperation between unrelated individuals, particularly across species, have not been thoroughly tested.
Purpose of the Study:
- To experimentally investigate the conditions necessary for the evolution of cooperation between different species.
- To test the hypothesis that pre-existing reciprocation and preferential benefit to cooperators are key factors.
- To demonstrate a laboratory model for the origin of interspecific cooperation.
Main Methods:
- Utilized a two-species laboratory system: Salmonella enterica ser. Typhimurium and a auxotrophic Escherichia coli mutant.
- Established reciprocation by having Salmonella consume E. coli's metabolic waste in lactose media.
- Ensured preferential benefit to cooperators using a spatially structured environment.
Main Results:
- Salmonella evolved to provide a costly amino acid to E. coli, demonstrating novel interspecific cooperation.
- This evolved cooperation was contingent on the presence of waste consumption (reciprocation) and spatial structure.
- Cooperation diminished or disappeared when these conditions were removed, highlighting their necessity.
Conclusions:
- Interspecific cooperation can be experimentally evolved under specific conditions.
- Pre-existing reciprocation and spatial structuring that favors cooperative genotypes are critical for the origin of cooperation between species.
- This work provides an experimental foundation for understanding the evolution of mutualistic interactions in nature.
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