Using environmental noise to hedge one's evolutionary bets

Bet-hedging is an adaptation strategy commonly used by organisms living in unpredictable environments: Each individual randomly expresses one of many possible phenotypes so that a subset of the population may survive. The random choice of phenotypes is usually attributed to stochastic biochemical processes internal to the organism, such as multi-stable dynamics of the gene regulatory network. Alternatively, the organism may rely on randomness that is present (and probably abundant) in the external environment. We illustrate the latter possibility using a model of "environment-to-phenotype mapping". That is, we let the organism's phenotype depend on an environmental signal, and numerically evolve such dependence to maximize the population growth rate. We show that, even when the signal is extremely noisy and uninformative of the true environment, the organism can still benefit from the signal by using it as a source of randomness for bet-hedging.