Evolution of intraspecific floral variation in a generalist-specialist pollination system.

Publisher: Oxford University Press Country of Publication: England NLM ID: 8809954 Publication Model: Print Cited Medium: Internet ISSN: 1420-9101 (Electronic) Linking ISSN: 1010061X NLM ISO Abbreviation: J Evol Biol Subsets: MEDLINE

Publication: January 2024- : [Oxford] : Oxford University Press
Original Publication: [Basel, Switzerland : Birkhäuser Verlag, c1988-

Flowers*/anatomy & histology ; Flowers*/physiology ; Pollination* ; Biological Evolution*; Phylogeny ; Animals ; Magnoliopsida/physiology ; Magnoliopsida/anatomy & histology ; Magnoliopsida/genetics ; Species Specificity

Intraspecific processes impact macroevolutionary patterns through individual variation, selection, and ecological specialization. According to the niche variation hypothesis, the broader ecological niche of generalist species results in an increased morphological variation among individuals either because they are constituted of diversified specialized individuals each exploiting a fraction of the species' niche or because they are constituted of true generalist individuals that experience relaxed selection. To test this hypothesis, we surveyed the individual floral morphology of species of Antillean Gesneriaceae, a group that has transitioned between specialization for hummingbird pollination and generalization multiple times throughout its evolutionary history. We characterized the profiles of corollas using geometric morphometrics and compared the intraspecific shape variance of specialists and generalists in a phylogenetic context. We used three approaches that differently accounted for the high dimensionality of morphological traits, the ancestral reconstruction of pollination syndromes over time, and the error associated with the estimation of the intraspecific variance. Our findings provide partial support for the niche variation hypothesis. If considering the whole shape in the analysis corroborated this idea, decomposing the shape into principal components indicated that not all aspects of the corolla exhibit the same pattern of variation. Specifically, pollination generalists tend to display greater intraspecific variation than specialists in terms of tubularity, but not of curvature. Accounting for the error in the variance estimation also reduced the support for the hypothesis, suggesting that larger sample sizes may be required to reach stronger conclusions. This study emphasizes the reciprocal influence between plants and their pollinators on floral morphology at different biodiversity scales and suggests that ecological strategies of species can affect patterns of morphological variation at macroevolutionary scales.
(© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Evolutionary Biology.)

05027-2018 Natural Sciences and Engineering Research Council of Canada (NSERC); PAPIIT-IN224920 Dirección General de Personal Académico; 9522-14 National Geographic Society

Keywords: Antillean Gesneriaceae; floral morphology; intraspecific variation; macroevolution; niche variation hypothesis; plant pollination strategies; pollination generalists; pollination specialists

Date Created: 20240309 Date Completed: 20241210 Latest Revision: 20241210

20241216

10.1093/jeb/voae028

38460029