Ref ID: 10391
Ref Type: Journal
Authors: Hingston, A. B. and Potts, B. M.
Pub Date: 2005
Journal Name: Austral Ecology
Volume: 30
Issue:
Start Page: 319
End Page: 324
ISBN/ISSN:
Keywords: behaviour/branch/canopy/deposition/Eucalyptus/Eucalyptus globulus/flower/globulus/high/interaction/mating/mating system/outcrossing/outcrossing rate/plant/pollination/pollination ecology/pollinator/pressure/rate/seed/seeds/selection/spatial/species/system/Tasmania/time/trait/tree/variation
Abstract: We tested the hypothesis that the previously recorded higher outcrossing rates and numbers of seeds per capsule from the upper, than from the lower, branches of trees of Eucalyptus globulus is the result of greater pollinator activity in the upper parts of the canopy. Observations of bird-pollinators on 23 trees, with flowers distributed evenly between the upper and lower halves of canopies, supported this hypothesis. Birds spent significantly more time foraging, and commenced foraging significantly more often, in the upper halves than in the lower halves of canopies. Flowers in the upper halves of E. globulus canopies would, therefore, be expected to receive greater quantities of outcross-pollen from bird-pollinators because they are usually visited more often and would receive a greater ratio of outcross- to self-pollen. Such systematic differences in foraging behaviour appear to be driven by aggressive interactions between bird pollinators. We propose that such within-canopy variation in pollinator activity and outcross-pollen deposition results in different selective pressures on the mating system and pollination syndrome in different parts of the canopy, resulting in balanced selection for these traits. Such spatial variation in pollinator activity within a canopy may help explain the high frequency of mixed mating systems and generalist pollination syndromes in animal-pollinated plant species
Notes: Entered by Brad Potts (05/06/2003)
Reprint: Not in File
Program: SPF Genetic Improvement
Project: A1
Deliverable: A1-3.4
Confidentiality: Confidential to All Partners
Availability: Authors
Report: Annual Report 2004/5
Type: Article
Address: B.M.Potts@utas.edu.au