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Abstract Detail



Pollination Biology

DELLINGER, AGNES S. [1], PENNEYS, DARIN S. [2], SCHOENENBERGER, JUERG [1].

Floral food-bodies and a special pollen dispersal mechanism in bird-pollinated Axinaea (Melastomataceae).

Pollen as the only reward for buzz-pollinating bees is characteristic for most Neotropical Melastomataceae. We present a novel and highly complex bird-pollination mechanism in the Central- and South American genus Axinaea. The pollination system of Axinaea involves food body rewards in the form of conspicuous, bulbous stamen appendages. Our study combines field observations with detailed analyses of stamen structure using high resolution X-ray computed tomography as well as with chemical and calorimetric assessments of the food body tissue. We show that the bulbous stamen appendages, which are consumed by various species of pollinating passerines (Thraupidae and Fringillidae) are multifunctional during the pollination process: (i) the appendages serve as visual attractants for the pollinating birds; (ii) they function as a bellows organ in a unique and complex pollen expulsion mechanism activated by the passerines while compressing the stamen appendages with their bills and removing them for consumption; and (iii) they provide a hexose-rich, highly nutritious (15100 J/g) food body reward for the pollinating birds. The discovery of this passerine pollination system in the mainly bee-pollinated Melastomataceae may serve as another example for a shift in pollination syndrome related to growth at higher elevations where bees are less efficient pollinators than birds.


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1 - University of Vienna, Department of Botany and Biodiversity Research, Rennweg 14, Vienna, A-1030, Austria
2 - California Academy of Sciences, Department of Botany, Golden Gate Park, 55 Music Concourse Drive, San Francisco, California, 94118, USA

Keywords:
Axinaea
Melastomataceae
bird-pollination
floral food body
floral structure.

Presentation Type: Oral Paper:Papers for Topics
Session: 32
Location: Firs South/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 10:15 AM
Number: 32009
Abstract ID:672
Candidate for Awards:None


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