Transience in the simulation of ring species

Biological ring species theoretically develop when an ancestral population expands around a geographic barrier and differentiates until terminal populations come back into contact. Adjacent populations are fertile; fertility declines with distance, and the terminal populations are not fertile. This study uses evolutionary algorithms to attempt to create artificial ring species using grid robots performing the Tartarus task with ISAc lists and string genes solving the Self Avoiding Walk (SAW) problem. Three experiments are done with the Tartarus robots. Fertility is shown to decrease with distance, but not to the extent that ring species are formed. Two experiments are done with SAW. These experiments produce sub-populations which satisfy all the criteria for biological ring species at the point in time when the ring closes. As evolution continues, the relationship between fertility and distance continues, but the terminal populations do not remain infertile. In addition, on both problems, record scores are achieved, suggesting that this model of evolution is a good optimizer for multi-optima problems like Tartarus and SAW which have many deceptive suboptima.