Data from: Hybridization and reproductive isolation between diploid Erythronium mesochoreum and its tetraploid congener E. albidum (Liliaceae)

Polyploidy has played an important role in angiosperm diversification, but how polyploidy contributes to reproductive isolation remains poorly understood. Most work has focused on postzygotic reproductive barriers, and the influence of ploidy differences on prezygotic barriers is understudied. To address these gaps, we quantified hybrid occurrence, interspecific self-compatibility differences, and the contributions of multiple pre- and postzygotic barriers to reproductive isolation between diploid Erythronium mesochoreum (Liliaceae) and its tetraploid congener E. albidum. Reproductive isolation between the study species was nearly complete, and naturally occurring hybrids were infrequent and largely sterile. Although postzygotic barriers effected substantial reproductive isolation when considered in isolation, the study species' spatial distributions and pollinator assemblages overlapped little, such that interspecific pollen transfer is likely uncommon. We did not find evidence that E. albidum and E. mesochoreum differed in mating systems, indicating that self-incompatibility release may not have fostered speciation in this system. Ultimately, we demonstrate that E. albidum and E. mesochoreum are reproductively isolated by multiple, hierarchically-operating barriers, and we add to the currently limited number of studies demonstrating that early acting barriers such as pollinator-mediated isolation can be important for effecting and sustaining reproductive isolation in diploid-polyploid systems.01_Flow Cytometry RF ValuesFlow cytometry relative fluorescence values used to assess hybrid occurrence at contact zones.02_Geographic Isolation DataData used to calculate the extent of geographic isolation between E. albidum and E. mesochoreum using floral visitors' intertegular spans.035_herb recordsHerbarium records used in the analysis of phenological differences between E. albidum and E. mesochoreumherbarium analysesR code for the herbarium analysesFL Phenology Null ModelR code for the field-based phenology modelphenology20102010 phenology data (see description in R script)phenology2010editedited 2010 phenology data (see R script for description)phenology20112011 phenology data (see R script for additional info)phenology2011editedited 2011 phenology file (see R script for details)Code for sd set sd mass and SIR code for analyses of seed set, seed mass, and SI releasepollination spreadsheet 2010 2011spreadsheet of hand-pollination data for analyses of seed set, seed mass, and SI release06_Pollen viability counts spreadsheet_for msData used for calculations of E. mesochoreum and hybrid pollen viabilit