DOI: 10.5061/dryad.c715s
title: Data from: Both morph- and species-dependent asymmetries affect reproductive barriers between heterostylous species

description: The interaction between floral traits and reproductive isolation is
 crucial to explaining the extraordinary diversity of angiosperms.
 Heterostyly, a complex floral polymorphism that optimizes outcrossing,
 evolved repeatedly and has been shown to accelerate diversification in
 primroses, yet its potential influence on isolating mechanisms remains
 unexplored. Furthermore, the relative contribution of pre- versus
 postmating barriers to reproductive isolation is still debated. No
 experimental study has yet evaluated the possible effects of heterostyly
 on pre- and postmating reproductive mechanisms. We quantify multiple
 reproductive barriers between the heterostylous Primula elatior (oxlip)
 and P. vulgaris (primrose), which readily hybridize when co-occurring, and
 test whether traits of heterostyly contribute to reproductive barriers in
 unique ways. We find that premating isolation is key for both species,
 while postmating isolation is considerable only for P. vulgaris;
 ecogeographic isolation is crucial for both species, while phenological,
 seed developmental, and hybrid sterility barriers are also important in P.
 vulgaris, implicating sympatrically higher gene flow into P. elatior. We
 document for the first time that, in addition to the aforementioned
 species-dependent asymmetries, morph-dependent asymmetries affect
 reproductive barriers between heterostylous species. Indeed, the
 interspecific decrease of reciprocity between high sexual organs of
 complementary floral morphs limits interspecific pollen transfer from
 anthers of short-styled flowers to stigmas of long-styled flowers, while
 higher reciprocity between low sexual organs favors introgression over
 isolation from anthers of long-styled flowers to stigmas of short-styled
 flowers. Finally, intramorph incompatibility persists across species
 boundaries, but is weakened in long-styled flowers of P. elatior, opening
 a possible backdoor to gene flow through intramorph pollen transfer
 between species. Therefore, patterns of gene flow across species
 boundaries are likely affected by floral morph composition of adjacent
 populations. To summarize, our study highlights the general importance of
 premating isolation and newly illustrates that both morph- and
 species-dependent asymmetries shape boundaries between heterostylous
 species.
description: Raw data from occurrence
 records and experiments performed to quantify strength and species- and
 morph-dependent asymmetries of reproductive isolation between Primula
 elatior and P. vulgaris.The excel file contains
 raw data of (i) number of 1x1 km grid cells from occurrence data of
 Switzerland that was used to estimate ecogeographic isolation (RIecogeo);
 (ii) number of pollen grains, diameter of pollen grains, anther and stigma
 positions, and anther-stigma distance from the pollen-transfer experiment
 that was used to estimate mechanical isolation (RImech); (iii) number of
 seeds, filled seeds, seedlings, and flowers, and proportion of fruits and
 survivors from the hand-pollination experiment that was used to estimate
 F1 seedling formation (RIseedling) and F1 survivorship (RIsurvivorship);
 (iv) number of plants and open flowers per census day, date of onset,
 peak, and end of flowering time, number of flowers, number of seeds and
 filled seeds from the common garden experiment that was used to estimate
 phenological isolation (RIphenoP), F1 phenology (RIphenoF1), F1 flower
 production (RIflower), and F1 seed set (RIseed set); and (v) number of
 seeds, filled seeds, and seedlings from the hand-pollination backcross
 experiment that was used to estimate F1 male sterility (RImale). Data for
 occurrence records and each experiment are presented in an individual
 worksheet. Names of column headings correspond with terms used in the
 original paper (Table 1).ECE-2016-04-00333.xlsx