Premium
Ecological differentiation facilitates fine‐scale coexistence of sexual and asexual Boechera
Author(s) -
Rushworth Catherine A.,
Windham Michael D.,
Keith Rose A.,
MitchellOlds Tom
Publication year - 2018
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1201
Subject(s) - biology , asexuality , apomixis , asexual reproduction , ecology , parthenogenesis , sexual reproduction , range (aeronautics) , ploidy , human sexuality , gene , genetics , embryo , gender studies , materials science , sociology , composite material
Premise of the Study Ecological differentiation ( ED ) between sexual and asexual organisms may permit the maintenance of reproductive polymorphism. Several studies of sexual/asexual ED in plants have shown that the geographic ranges of asexuals extend beyond those of sexuals, often in areas of higher latitude or elevation. But very little is known about ED at fine scales, wherein coexistence of sexuals and asexuals may be permitted by differential niche occupation. Methods We used 149 populations of sexual and apomictic lineages in the genus Boechera (rock cress) collected across a portion of this mustard's vast range. We characterized reproductive mode, ploidy, and species identity or hybrid parentage of each individual, and then used a multipronged statistical approach to (1) identify ED between sexuals and asexuals; (2) investigate the impacts of two confounding factors, polyploidy and hybridization, on ED ; and (3) determine the environmental variables underlying ED . Key Results We found that sexuals and asexuals are significantly ecologically differentiated across the landscape, despite fine‐scale interdigitation of these two reproductive forms. Asexual reproduction was strongly associated with greater disturbance, reduced slope, and greater environmental variability. Although ploidy had little effect on the patterns observed, hybridization has a unique impact on the relationships between asexual reproduction and specific environmental variables. Conclusions Ecological differentiation along the axes of disturbance, slope, and climatic variability, as well as the effects of heterozygosity, may contribute to the maintenance of sexuality and asexuality across the landscape, ultimately impacting the establishment and spread of asexual lineages.