Reproductive isolation emerges from coordinated barriers during mating system divergence in plants

作者：Ana García-Muñoz, Camilo Ferrón, Enrica Olivieri, Mohamed Abdelaziz, A. Jesus Muñoz-Pajares · 发表于：bioRxiv (Cold Spring Harbor Laboratory) · 年份：2026 · DOI：10.64898/2026.04.26.720968 · 研究领域：Plant and animal studies、Genetic diversity and population structure、Animal Behavior and Reproduction

Abstract Background and Aims Understanding how reproductive barriers combine to restrict gene flow remains a central challenge in speciation research. Although reproductive isolation is inherently a composite process, most empirical studies have focused on individual barriers in isolation, limiting our ability to capture their joint effects particularly in systems undergoing evolutionary transitions such as shifts in mating system. Methods Here, we provide a comprehensive, life-cycle-wide quantification of reproductive isolation between two closely related species of the Erysimum incanum complex that differ strikingly in mating system: the predominantly selfing E. incanum and the outcrossing E. wilczekianum . Key Results By integrating ecological, phenological, behavioural, and post-pollination components, we show that total reproductive isolation is nearly complete (T≈0.999), but overwhelmingly driven by pre-pollination barriers. Ecogeographical differentiation and, most prominently, pollinator-mediated isolation dominate, with pollinators exhibiting a strong bias toward E. wilczekianum . Floral traits linked to mating system divergence, particularly flower size, emerge as key drivers of assortative mating, supporting their role as “magic traits” coupling ecological divergence with reproductive isolation. In contrast, post-pollination barriers are weaker but strongly asymmetric. Hybrid seed formation is largely prevented when E. wilczekianum acts as the maternal parent, cons...