Incomplete partitioning of pollinators by Linum suffruticosum and its coflowering congeners Pérez Barrales, María del Rocío Armbruster, William Scott Character displacement Heterostyly Inaccuracy Interspecific pollen transfer Linaceae Pollen tube Pollination ecotypes Pollinator importance Reproductive interference This work was supported by funding from The Royal Society (Research Grant 13525) and the Spanish Ministry of Science and Innovation (grant PID2021-127264NB-I00 by MCIN/AEI/10.13039/501100011033 ERDF A way of making Europe) to R.P.B. The fieldwork of R.P.B. was supported by a postdoctoral grant funded by US NSF to W.S.A. (DEB-0444754) and the postdoctoral JDC program from the Spanish Ministerio de Ciencia e Innovacion. The open access funding was provided by Universidad de Granada/CBUA. PremiseLinum suffruticosum shows variations in pollinator fit, pollen pickup, and local pollinators that predict pollen deposition rates. The species often coflowers with other Linum species using the same pollinators. We investigated whether L. suffruticosum trait variation could be explained by local patterns of pollinator sharing and associated evolution to reduce interspecific pollen transfer. MethodsPollinator observations were made in different localities (single species, coflowering with other congeners). Floral traits were measured to detect differences across populations and from coflowering species. Reproductive costs were quantified using interspecific hand pollinations and measures of pollen-tube formation, combined with observations of pollen arrival on stigmas and pollen-tube formation after natural pollination in allopatric and sympatric localities. ResultsThe size and identity of the most important pollinator of L. suffruticosum and whether there was pollinator sharing with coflowering species appeared to explain floral trait variation related to pollinator fit. The morphological overlap of the flowers of L. suffruticosum with those of coflowering species varied, depending on coflowering species identity. A post-pollination incompatibility system maintains reproductive isolation, but conspecific pollen-tube formation was lower after heterospecific pollination. Under natural pollination at sites of coflowering with congeners, conspecific pollen-tube formation was lower than at single-species localities. ConclusionsTrait variation in L. suffruticosum appears to respond to the most important local pollinator. Locally, incomplete pollinator partitioning might cause interspecific pollination, imposing reproductive costs. These reproductive costs may generate selection on floral traits for reduced morphological overlap with coflowering congeners, leading to the evolution of pollination ecotypes. 2023-07-13T11:31:20Z 2023-07-13T11:31:20Z 2023-05-10 info:eu-repo/semantics/article Pérez‐Barrales, R., and W. S. Armbruster. 2023. Incomplete partitioning of pollinators by Linum suffruticosum and its coflowering congeners. American Journal of Botany 110(6): e16181. [https://doi.org/10.1002/ajb2.16181] https://hdl.handle.net/10481/83694 10.1002/ajb2.16181 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional Wiley