On the importance of being stable - evolutionarily frozen species can win in fluctuating environment

Abstract

The ability of organisms to adaptively respond to environmental changes (evolvability) is usually considered to be an important advantage in interspecific competition. It has been suggested, however, that evolvability could be a double-edged sword that could present a serious handicap in fluctuating environments. The authors of this counterintuitive idea have published only verbal models to support their claims.\n\nHere we present the results of individual-based stochastic modelling of competition between two asexual species differing only by their evolvability. They show that, in changeable environments, less evolvable species could outperform their more evolvable competitors in a broad area of a parameter space, regardless of whether the conditions fluctuated periodically or aperiodically. Highly evolvable species prospered better nearly all the time; however, they sustained a higher probability of extinction during rare events of the rapid transient change of conditions.\n\nOur results offer an explanation of why sexually reproducing species, with their reduced capacity to respond adaptively to local or temporal environmental changes, prevail in most eukaryotic taxa in nearly all biotopes on the surface of Earth. These species may suffer several important disadvantages in direct competitive battles with asexual species; however, they might win in changeable environments in the more important sorting-according-to-stability war.