Variation in floral longevity between populations of Campanula rotundifolia (Campanulaceae) in response to fitness accrual rate manipulation

Floral longevity, the time between corolla expansion and senescence, contributes directly and indirectly to a plant's overall fitness. Though mating opportunities for insect-pollinated species often differ among populations, few empirical studies have addressed whether floral longevity varies i...

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Bibliographic Details
Published in:American journal of botany 2005-10, Vol.92 (10), p.1714-1722
Main Author: Giblin, David E
Format: Article
Language:English
Subjects:
alpine tundra
Campanula rotundifolia
Campanulaceae
Canyons
Colorado
conditional response
Corolla
fitness accrual rate
floral longevity
Flowers
geographic variation
geographical variation
insects
Longevity
microclimate
Modeling
mountains
phenology
Plants
Pollen
pollen limitation
Pollinating insects
Pollination
Pollinators
Reproductive Biology
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Summary:Floral longevity, the time between corolla expansion and senescence, contributes directly and indirectly to a plant's overall fitness. Though mating opportunities for insect-pollinated species often differ among populations, few empirical studies have addressed whether floral longevity varies in a manner consistent with these differences. I conducted experiments at thermally distinct sites to examine whether the prevailing floral longevity model predicted such variation between a montane and an alpine population of Campanula rotundifolia. Staminate phase duration was significantly shorter for montane vs. alpine C. rotundifolia flowers in the presence of pollinators, but significantly longer when pollinators were excluded. Montane flowers had a significantly higher female fitness accrual rate, significantly shorter total longevities, and, unlike alpine flowers, were not pollen-limited. Delaying pollinator access to pistillate phase flowers significantly increased total longevity in alpine flowers only. Significant differences in total longevity between populations resulted from an extended pistillate phase in alpine flowers. Overall, the prevailing model accurately predicted the total floral longevity trends found here. However, I provide novel evidence for geographic and gender-specific plasticity in the floral longevity response to fitness accrual rate variation, suggesting C. rotundifolia populations in this study may be attuned to local schedules of pollinator activity.
ISSN:0002-9122
1537-2197
DOI:10.3732/ajb.92.10.1714