Architectural traits constrain the evolution of unisexual flowers and sexual segregation within inflorescences: an interspecific approach
5 affiliations
- 1Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (CSIC), Spain
- 2Department of Ecology and Evolution, University of Lausanne, Switzerland
- 3Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Spain
- 4Centro de Ecologia Funcional, Universidade de Coimbra, Portugal
- 5Department of Botany, Swedish Museum of Natural History, Sweden
Abstract
Male and female unisexual flowers have repeatedly evolved from the ancestral bisexual flowers in different lineages of flowering plants. This sex specialization in different flowers often occurs within inflorescences. We hypothesize that inflorescence architecture may impose a constraint on resource availability for late flowers, potentially leading to different optima in floral sex allocation and unisexuality. Under this hypothesis we expect that inflorescence traits increasing the difference in resource availability between early and late flowers would be phylogenetically correlated with a higher level of sexual specialization. To test this hypothesis, we performed a comparative analysis of inflorescence traits (inflorescence size, number of flowers and flower density) in the sunflower family, which displays an extraordinary variation in floral sexual specialization at the inflorescence level, i.e. hermaphroditic, gynomonoecious and monoecious species. We found that species with a complete sex separation in unisexual flowers (monoecy) had significantly denser inflorescences. Furthermore, those species arranging their flowers in denser inflorescences also showed greater differences in the size of early and late fruits, a proxy of resource variation between flowers. Our findings support the idea that floral sexual specialization and consequently sexual segregation may be the consequence of different floral sex allocation optima driven by the sequential development of flowers that results in a persistent resource decline from earlier to later flowers.
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BibTeX
@article{torices2026architectural,
title = {{Architectural traits constrain the evolution of unisexual flowers and sexual segregation within inflorescences: an interspecific approach}},
author = {Rubén Torices and Ana Afonso and Arne A. Anderberg and José M. Gómez and Marcos Méndez},
journal = {Peer Community Journal},
year = {2026},
month = aug,
doi = {10.24072/pcjournal.739},
url = {https://doi.org/10.24072/pcjournal.739},
note = {CC BY},
}
RIS
TY - JOUR
TI - Architectural traits constrain the evolution of unisexual flowers and sexual segregation within inflorescences: an interspecific approach
AU - Rubén Torices
AU - Ana Afonso
AU - Arne A. Anderberg
AU - José M. Gómez
AU - Marcos Méndez
PY - 2026
DA - 2026/08/31
JO - Peer Community Journal
DO - 10.24072/pcjournal.739
UR - https://doi.org/10.24072/pcjournal.739
AB - Male and female unisexual flowers have repeatedly evolved from the ancestral bisexual flowers in different lineages of flowering plants. This sex specialization in different flowers often occurs within inflorescences. We hypothesize that inflorescence architecture may impose a constraint on resource availability for late flowers, potentially leading to different optima in floral sex allocation and unisexuality. Under this hypothesis we expect that inflorescence traits increasing the difference in resource availability between early and late flowers would be phylogenetically correlated with a higher level of sexual specialization. To test this hypothesis, we performed a comparative analysis of inflorescence traits (inflorescence size, number of flowers and flower density) in the sunflower family, which displays an extraordinary variation in floral sexual specialization at the inflorescence level, i.e. hermaphroditic, gynomonoecious and monoecious species. We found that species with a complete sex separation in unisexual flowers (monoecy) had significantly denser inflorescences. Furthermore, those species arranging their flowers in denser inflorescences also showed greater differences in the size of early and late fruits, a proxy of resource variation between flowers. Our findings support the idea that floral sexual specialization and consequently sexual segregation may be the consequence of different floral sex allocation optima driven by the sequential development of flowers that results in a persistent resource decline from earlier to later flowers.
SN - 2804-3871
ER -