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Data from: Alteration of (frequency-dependent) fitness in time-shift experiments reveals cryptic co-evolution and uncoordinated stasis in a virtual Jurassic Park

Citation

Luo, Tian-tong; Zhu, Jian-long; Reitan, Trond; Yedid, Gabriel (2019), Data from: Alteration of (frequency-dependent) fitness in time-shift experiments reveals cryptic co-evolution and uncoordinated stasis in a virtual Jurassic Park, Dryad, Dataset, https://doi.org/10.5061/dryad.67506q4

Abstract

Digital evolution is a computer-based instantiation of Darwinian evolution in which short self-replicating computer programs compete, mutate, and evolve. It is an excellent experimental platform for addressing topics in both short-term and long-term evolution, such as whether co-evolving multispecies communities are dominated more by biotic or abiotic factors, and whether evolutionary stasis affects performance as well as ecological profile. We evolved model communities with ecological interdependence among community members, which were subjected to two principal types of mass extinction: a pulse extinction that killed randomly, and a selective press extinction involving an alteration of the abiotic environment to which the communities had to adapt. These treatments were applied at two different strengths (Strong and Weak), along with unperturbed Control experiments. We performed several kinds of competition experiments using simplified versions of these communities to see whether long-term stability that was implied previously by ecological and phylogenetic metrics was also reflected in terms of performance, i.e. whether fitness was static over long periods of time. Results from Control and Weak treatment communities revealed almost completely transitive evolution, while Strong treatment communities showed higher incidences of intransitivity, with pre-treatment ecotypes often able to displace some of their post-recovery successors. However, pre-treatment carryovers more often had lower fitness in mixed communities than in their own fully native conditions. Replacement and invasion experiments pitting single ecotypes against pre-treatment reference communities showed that many of the invading ecotypes could measurably alter the fitnesses of one or more residents, usually with depressive effects, and that the strength of these effects increased over time even in the most stable communities. However, invaders taken from Strong treatment communities often had little to no effect on resident performance. While we detected periods of time when the fitness of a particular evolving ecotype remained static, this stasis was not permanent and was uncoordinated, never affecting an entire community at once. Our results lend support to the fitness-deterioration interpretation of the Red Queen hypothesis, and highlight community context-dependence in determining fitness, the shaping of communities by both biotic factors and abiotic forcing, and the illusory nature of evolutionary stasis. Our results also demonstrate the potential of digital evolution studies to illuminate many aspects of evolution in interacting multispecies communities.

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