The Pollination Biology of Burmeistera (Campanulaceae): Specialization and Syndromes

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Abstract

<div class="line" id="line-7"> The floral traits of plants with specialized pollination systems both facilitate the primary pollinator and restrict other potential pollinators. To explore interactions between pollinators and floral traits of the genus&nbsp; <i> Burmeistera </i> , I filmed floral visitors and measured pollen deposition for 10 species in six cloud forest sites throughout northern Ecuador. Nine species were primarily bat&hyphen;pollinated (84&ndash;100% of pollen transfer); another ( <i> B. rubrosepala </i> ) was exclusively hummingbird&hyphen;pollinated. According to a principal components analysis of 11 floral measurements, flowers of&nbsp; <i> B. rubrosepala </i> &nbsp;were morphologically distinct. Floral traits of all species closely matched traditional ornithophilous and chiropterophilous pollination syndromes; flowers of&nbsp; <i> B. rubrosepala </i> were bright red, lacked odor, opened in the afternoon, and had narrow corolla apertures and flexible pedicels, which positioned them below the foliage. Flowers of the bat&hyphen;pollinated species were dull&hyphen;colored, emitted odor, opened in the evening, and had wide apertures and rigid pedicels, which positioned them beyond the foliage. Aperture width appeared most critical to restricting pollination; hummingbirds visited wide flowers without contacting the reproductive parts, and bats did not visit the narrow flowers of&nbsp; <i> B. rubrosepala </i> . Aperture width may impose an adaptive trade&hyphen;off that favors the high degree of specialization in the genus. Other floral measurements were highly variable amongst bat&hyphen;pollinated species, including stigma exsertion, calyx lobe morphology, and pedicel length. Because multiple species of&nbsp; <i> Burmeistera </i> &nbsp;often coexist, such morphological diversity may reduce pollen competition by encouraging pollinator fidelity and/or spatially partitioning pollinator's bodies.</div>
Original languageAmerican English
JournalAmerican Journal of Botany
Volume93
StatePublished - 2003

Disciplines

  • Life Sciences

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