Generalized pollination maintains disassortative pollen transfer in a distylous tropical shrub
- 1Departamento de Biología Vegetal y Ciencias del Suelo, Facultad de Biología, Universidade de Vigo, Campus As Lagoas-Marcosende, Vigo E-36310, Spain
Abstract
Background and Aims: Distylous plants are expected to promote accurate intermorph pollen transfer through reciprocal positioning of sexual organs, yet many species are visited by taxonomically diverse pollinator assemblages. Whether generalized pollination compromises mating accuracy in such systems remains unclear.
Methods: Single-visit experiments were conducted to quantify pollen transfer in the distylous Caribbean shrub Morinda royoc (Rubiaceae). Pollen-size dimorphism was used to distinguish morph-specific pollen and to estimate both total pollen deposition and the proportion of disassortative (reciprocal) pollen delivered by different visitor groups.
Key Results: Multiple pollinator taxa, including butterflies, hummingbirds and bees, deposited predominantly intermorph pollen on stigmas. Although pollination effectiveness was unevenly distributed across the visitor assemblage and concentrated in a subset of species, the directionality of pollen flow remained consistently biased towards intermorph transfer across taxa. Variation in floral traits, including corolla tube dimensions, anther height, style length and stigmatic surface area, did not explain differences in the proportion of reciprocal pollen deposited.
Conclusions: These findings indicate that reciprocal floral architecture can maintain mating accuracy under generalized pollination. Although quantitative contributions to pollination vary among visitors, the qualitative component of pollen transfer appears robust to differences in pollinator identity. Structural reciprocity might therefore stabilize reproductive processes in distylous systems exposed to variable pollinator assemblages.
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BibTeX
@article{navarro2026generalized,
title = {{Generalized pollination maintains disassortative pollen transfer in a distylous tropical shrub}},
author = {Luis Navarro},
journal = {Annals of Botany},
year = {2026},
month = jul,
doi = {10.1093/aob/mcag199},
url = {https://doi.org/10.1093/aob/mcag199},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Generalized pollination maintains disassortative pollen transfer in a distylous tropical shrub
AU - Luis Navarro
PY - 2026
DA - 2026/07/08
JO - Annals of Botany
DO - 10.1093/aob/mcag199
UR - https://doi.org/10.1093/aob/mcag199
AB - Background and Aims: Distylous plants are expected to promote accurate intermorph pollen transfer through reciprocal positioning of sexual organs, yet many species are visited by taxonomically diverse pollinator assemblages. Whether generalized pollination compromises mating accuracy in such systems remains unclear. Methods: Single-visit experiments were conducted to quantify pollen transfer in the distylous Caribbean shrub Morinda royoc (Rubiaceae). Pollen-size dimorphism was used to distinguish morph-specific pollen and to estimate both total pollen deposition and the proportion of disassortative (reciprocal) pollen delivered by different visitor groups. Key Results: Multiple pollinator taxa, including butterflies, hummingbirds and bees, deposited predominantly intermorph pollen on stigmas. Although pollination effectiveness was unevenly distributed across the visitor assemblage and concentrated in a subset of species, the directionality of pollen flow remained consistently biased towards intermorph transfer across taxa. Variation in floral traits, including corolla tube dimensions, anther height, style length and stigmatic surface area, did not explain differences in the proportion of reciprocal pollen deposited. Conclusions: These findings indicate that reciprocal floral architecture can maintain mating accuracy under generalized pollination. Although quantitative contributions to pollination vary among visitors, the qualitative component of pollen transfer appears robust to differences in pollinator identity. Structural reciprocity might therefore stabilize reproductive processes in distylous systems exposed to variable pollinator assemblages.
SN - 0305-7364
SN - 1095-8290
ER -