J Syst Evol ›› 2023, Vol. 61 ›› Issue (1): 213-226.DOI: 10.1111/jse.12897

• Research Articles • Previous Articles     Next Articles

Current and historical factors drive variation of reproductive traits in unisexual mosses in Europe: A case study

María Teresa Boquete1*, Zulema Varela2,3, José Angel Fernández2, Juan Antonio Calleja4,5, Cristina Branquinho3, Antonina Chilà2, Nils Cronberg6, Ricardo Cruz de Carvalho3, Cristiana Aleixo3, Belén Estébanez‐Pérez4, Verónica Fernández‐González2, Andrés Baselga7, Carola Gómez‐Rodríguez2, Juana María González‐Mancebo8, Sebastien Leblond9, Javier Martínez‐Abaigar10, Nagore G. Medina4,5, Encarnación Núñez‐Olivera11, Jairo Patiño8,12, Rubén Retuerto2, Antón Vázquez‐Arias2, Alain Vanderpoorten13, Harald G. Zechmeister14 , and Jesús Ramón Aboal2   

  1. 1 Department of Evolutionary Ecology, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
    2 Department of Functional Biology, CRETUS, Universidade de Santiago de Compostela, Santiago, Spain
    3 Global Change and Sustainablility Institute, cE3c ‐ Centre for Ecology, Evolution and Environmental Changes & CHANGE, Faculdade de Ciências, Universidade de Lisboa, Lisboa 1749‐016, Portugal
    4 Departamento de Biología (Botánica), Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
    5 Centro de Investigación en Biodiversidad y Cambio Global, Madrid, Spain
    6 Department of Biology, Lund University, Lund, Sweden
    7 Department of Zoology, Genetics and Physical Anthropology, CRETUS, Universidade de Santiago de Compostela, Santiago, Spain
    8 Department of Botany, Ecology and Plant Physiology, Unit of Botany, Universidad de la Laguna, San Cristóbal de La Laguna, Spain
    9 UMS Patrinat (OFB, MNHN, CNRS), Paris, France
    10Department of Agriculture and Food, Unit of Botany, Universidad de la Rioja, La Rioja, Spain
    11Department of Agriculture and Food, Unit of Plant Physiology, Universidad de la Rioja, La Rioja, Spain
    12Island Ecology and Evolution Research Group, Instituto de Productos Naturales y Agrobiología (IPNA‐CSIC), Tenerife, Spain
    13Botany Institute, University of Liège, Liège, Belgium
    14Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria

    Author for correspondence. E‐mail: teresa.boquete@gmail.com; teresaboquete@ebd.csic.es
  • Received:2021-11-17 Accepted:2022-05-27 Online:2022-06-01 Published:2023-01-01

Abstract: Unisexual bryophytes provide excellent models to study the mechanisms that regulate the frequency of sexual versus asexual reproduction in plants, and their ecological and evolutionary implications. Here, we determined sex expression, phenotypic sex ratio, and individual shoot traits in 242 populations of the cosmopolitan moss Pseudoscleropodium purum spanning its whole distributional range. We tested whether niche differentiation, sex-specific differences in shoot size, and biogeographical history explained the spatial variation of reproductive traits. We observed high levels of sex expression and predominantly female-biased populations, although both traits showed high intraspecific variation among populations. Sex expression and sex ratio were partly explained by current macroscale environmental variation, with male shoots being less frequent at the higher end of the environmental gradients defined by the current distribution of the species. Female bias in population sex ratio was significantly lower in areas recolonized after the last glacial maximum (recent populations) than in glacial refugia (long-term persistent populations). We demonstrated that reproductive trait variation in perennial unisexual mosses is partially driven by macroscale and historical environmental variation. Based on our results, we hypothesize that sexual dimorphism in environmental tolerance and vegetative growth contribute to sex ratio bias over time, constraining the chances of sexual reproduction, especially in long-term persistent populations. Further studies combining genetic analyses and population monitoring should improve our understanding of the implications of the intraspecific variation in the frequency of sexual versus asexual reproduction in bryophyte population fitness and eco-evolutionary dynamics.

Key words: asexual reproduction, biogeographic distribution, phenotypic sex ratio, sex expression, sexual dimorphism, sexual reproduction