nice guys finish last, sort of

I recently read a really neat paper A Mixture of “Cheats” and “Co-Operators” Can Enable Maximal Group Benefit in PLoS biology.

In this paper, the authors considered the problem of a group of bacteria living together. The bacteria can make proteins, which are needed for metabolizing sugars ("cooperators"), but which cost energy to make, or they can simply use the proteins surrounding them while producing none ("cheats"). They then did experiments to work out which balance of co-operators and cheaters allowed the population to grow the fastest.

The result is quite surprising: adding some cheaters makes the population grow faster than a population of all cooperators.

Essentially, what happens is that, when there is lots of proteins around, the cooperators have plenty of sugar, so they slow down protein production. When there's a shortage of sugars however, the cooperators produce more of the proteins.

Adding some cheats to the population reduces the sugar supply, driving the cooperators to produce more of the proteins, allowing the population to get more sugar, and thus to grow faster.

This is a very interesting result, and may tell us a lot about group dynamics in competitive-cooperative environments.