On the importance of being stable: evolutionarily frozen species can win in fluctuating environments

Abstract

The ability of organisms to respond adaptively 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 handicap in fluctuating environments. The authors of this counterintuitive idea have published only verbal models to support their claims. Here, we present the results of individual-based stochastic modelling of competition between two asexual species that differ 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. 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. It explains why sexual species, with their reduced capacity to respond adaptively to local or temporal environmental changes, prevail in nearly all biotopes.