An interactive heuristic model to test ecological and evolutionary hypotheses on incipient polyploid species

Abstract

Polyploidization is associated with lineage-specific changes that promote divergence and speciation. Knowledge about the establishment of neopolyploids is fragmentary. We use an open-source multi-agent software to build a scalable easy-to-use command center for analysing complex diploid-polyploid interactions. The workspace is a multilayered environment whose eco-variables fluctuate between generations. Reproductive syndromes, recombinant/clonal inheritance and complex traits (adaptivity, niche breadth, dispersal) are used to elicit fitness values and monitor population spatial dynamics. Neopolyploidization was recurrent, polytopic and heterogeneous in time. Increasing rates of unreduced gametes accelerated the establishment of neopolyploids but removed the role of triploids. Under standard rates and heterogeneous environment, model-based evidence shows that (1) a large proportion of polyploidization events are unsuccessful, (2) parental traits and local conditions prime a loss of diploid fitness that benefited eco-geographic structured polyploid success, (3) self-fertility and apomixis improve the rate of polyploidization, and shorten the time required for demographic establishment, and (4) ecological niche shifts promote cytotype coexistence, but niche expansion favors establishment and foster cytotype displacement. The modelling framework offers opportunities for in-depth lineage-specific analyses of the spatiotemporal dynamics and evolutionary differentiation in diploid-polyploid systems.