Research by IIGB’s Joel Sachs shows natural selection favors cheaters

Mutualisms, which are interactions between members of different species that benefit both parties, are found everywhere — from exchanges between pollinators and the plants they pollinate, to symbiotic interactions between us and our beneficial microbes.

Natural selection — the process whereby organisms better adapted to their environment tend to survive and produce more offspring — predicts, however, that mutualisms should fall apart. Individuals that gain from the cooperation of others but do not reciprocate (so-called cheaters) should arise and destabilize mutualisms. Yet to date, surprisingly little evidence of such cheating or destabilization exists.

A team of biologists at the University of California, Riverside, has now found strong evidence of this cheating.  Focusing on the interaction between nitrogen-fixing bacteria, or rhizobia, and their legume hosts spanning about 530 miles of California habitat, the researchers found that natural selection in their study populations favors cheating rhizobia.

Read the full story here.