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Fitness consequences of floral variation in Senecio jacobaea (Asteraceae): evidence from a segregating hybrid population and a resource manipulation experiment

Author:
  • Stefan Andersson
Publishing year: 2001
Language: English
Pages: 17-24
Publication/Series: Biological Journal of the Linnean Society
Volume: 74
Issue: 1
Document type: Journal article
Publisher: Linnean Society of London

Abstract english

The present study examines some of the ecological factors that might exert selection on floral morphology in Senecio jacobaea, a self-sterile composite which exhibits geographic variation in the frequency of rayed and discoid individuals. Regression analyses of phenotypic data from a large, segregating hybrid population, established in a semi-natural (garden) environment and studied over a 2-year period, revealed a negative relationship between the size of the rays and the average germination rate of the maternal seed crop, a pattern that can be attributed to the reduced germination speed of achenes from ray florets. There was no effect of ray size on the amount of cross-pollination achieved, the proportion of heads infested by larvae of seed flies (Pegohylemyia) and the amount of resources retained for the next flowering season. The lack of resource costs was also apparent in a manipulation experiment with greenhouse-grown plants of the rayed phenotype: artificial removal of all rays at the early bud or flowering stage had no detectable effect on subsequent flower and fruit development, regardless of whether the plants experienced high or low water stress. Given these and other observations, I hypothesize that plant-animal interactions and resource costs sometimes play a minor role in exerting selection on flower morphology and that spatially varying selection on germination behaviour accounts for some of the morph frequency variation in S. jacobaea. (C) 2001 The Linnean Society of London.

Keywords

  • Ecology

Other

Published
  • ISSN: 0024-4066
Stefan Andersson
E-mail: stefan [dot] andersson [at] biol [dot] lu [dot] se

Professor

Biodiversity

+46 46 222 44 08

E-A322

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Research group

Plant Biology

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Doctoral students and Postdocs

PhD students, main supervisor

Gróa Valgerdur Ingimudardóttir

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