  In biology and ecology, individuals or communities of individuals living in
unpredictable environments often alternate between different evolutionary
strategies to spread and reduce risks. Such behavior is commonly referred to as
"bet-hedging." Long-term survival probabilities and population sizes can be
much enhanced by exploiting such hybrid strategies. Here, we study the simplest
possible birth-death stochastic model in which individuals can choose among a
poor but safe strategy, a better but risky alternative, or a combination of
both. We show analytically and computationally that the benefits derived from
bet-hedging strategies are much stronger for higher environmental variabilities
(large external noise) and/or for small spatial dimensions (large intrinsic
noise). These circumstances are typically encountered by living systems, thus
providing us with a possible justification for the ubiquitousness of
bet-hedging in nature.
