PT  - JOURNAL ARTICLE
AU  - J. Flegr
AU  - P. Ponížil
TI  - On the advantages of evolutionary passivity in fluctuating environments: could sex be the preadaptation for the stability-based sorting?
AID  - 10.1101/139030
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 139030
4099  - http://biorxiv.org/content/early/2017/05/17/139030.short
4100  - http://biorxiv.org/content/early/2017/05/17/139030.full
AB  - The ability of organisms to adaptively respond to environmental changes (evolvability) is usually considered to be an important advantage in interspecies competition. It has been suggested, however, that evolvability could be a double-edged sword that could turn into a serious handicap in fluctuating environments. The authors of this dissident idea have published only verbal models to support their claims.Here we present the results of individual-based stochastic modelling. They show that, in changeable environments, less evolvable species could outperform its more evolvable competitor 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 rapid transient change of conditions.Our results offer an alternative explanation of why sexually reproducing species, with their reduced capacity to respond adaptively to environmental changes, prevail in most eukaryotic taxa in nearly all biotopes on the surface of Earth. These species often suffer several important disadvantages in direct competition with asexual species; however, they mostly win in changeable environments in the more important sorting-according-to-stability battle.Significance Statement Lower evolvability is one of many ecological and evolutionary disadvantages of sexual species. G.C. Williams suggested in his 1975 book that the limited evolvability of sexual species could, paradoxically, be the reason for their evolutionary success. Using a stochastic model, we confirmed that in a fluctuating environment the less evolvable species often wins over its more evolvable competitor. More evolvable species could adapt to temporarily changed conditions, but when the conditions quickly flip back to normal they are unable to adapt quickly enough and thus go extinct. The evolutionary opportunism of more evolvable asexual species could be the reason for the predominance of sexual species in most environments on the Earth’s surface.