The researchers created 192 pools in which the bacteria could grow and interact. The bacteria could migrate among pools, and when migration occurred among neighboring pools the three strains formed multi-pool patches.
"The restrained patches, the ones that grew slower, seemed to last longer and the unrestrained patches, the ones that grew faster, burned themselves out faster," Nahum said.
To understand the process, imagine a community of three strains, Rock, Paper and Scissors, and then imagine the emergence of an unrestrained supercompetitor, Rock* (rock star), that is able to displace Scissors even faster than regular Rock can. But that also makes Rock* a better competitor against Rock, the researchers said. Eventually Rock* will be a victim of its own success, being preyed upon by Paper.
The irony, Kerr said, is that "by chasing your victim faster you actually help out the guy who's chasing you." Restraining exploitive behavior is beneficial to the patch in the long run, he said, and is a realistic embodiment of the proverb "The enemy of my enemy is my friend."
"In patches with faster growth, members of the unrestrained patch burn through their victims and then are left to face their victims' victims, their own enemies," he said.
The observed effect only applies to structured communities with limited migration, the researchers said. In an unstructured community with greater migration and mixing, a species that curbed its aggressiveness would not reduce its chances of being engulfed by its enemy.
The findings have potential implications for other ecological systems, including mating systems of certain lizards that could have analogs among some reptiles, fish, birds and insects.
|Contact: Vince Stricherz|
University of Washington