, Volume 150, Issue 3, pp 398–408

Pollinator-mediated assortative mating in mixed ploidy populations of Chamerion angustifolium (Onagraceae)


  • Brad F. Kennedy
    • Department of Integrative BiologyUniversity of Guelph
    • Department of Biological SciencesSimon Fraser University
  • Holly A. Sabara
    • Department of Integrative BiologyUniversity of Guelph
  • Dan Haydon
    • Department of Integrative BiologyUniversity of Guelph
    • Division of Environmental and Evolutionary BiologyUniversity of Glasgow
    • Department of Integrative BiologyUniversity of Guelph
Population Ecology

DOI: 10.1007/s00442-006-0536-7

Cite this article as:
Kennedy, B.F., Sabara, H.A., Haydon, D. et al. Oecologia (2006) 150: 398. doi:10.1007/s00442-006-0536-7


Establishment of polyploid individuals within diploid populations is theoretically unlikely unless polyploids are reproductively isolated, pre-zygotically, through assortative pollination. Here, we quantify the contribution of pollinator diversity and foraging behaviour to assortative pollen deposition in three mixed-ploidy populations of Chamerion angustifolium (Onagraceae). Diploids and tetraploids were not differentiated with respect to composition of insect visitors. However, foraging patterns of the three most common insect visitors (all bees) reinforced assortative pollination. Bees visited tetraploids disproportionately often and exhibited higher constancy on tetraploids in all three populations. In total, 73% of all bee flights were between flowers of the same ploidy (2x–2x, 4x–4x); 58% of all flights to diploids and 83% to tetraploids originated from diploid and tetraploid plants, respectively. Patterns of pollen deposition on stigmas mirrored pollinator foraging behaviour; 73% of all pollen on stigmas (70 and 75% of pollen on diploid and tetraploid stigmas, respectively) came from within-ploidy pollinations. These results indicate that pollinators contribute to high rates of pre-zygotic reproductive isolation. If patterns of fertilization track pollen deposition, pollinator–plant interactions may help explain the persistence and spread of tetraploids in mixed-ploidy populations.


FireweedReproductive isolationPollinator constancyPollen depositionPolyploidy

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© Springer-Verlag 2006