, Volume 156, Issue 2, pp 341–350 | Cite as

Combined effects of inflorescence architecture, display size, plant density and empty flowers on bumble bee behaviour: experimental study with artificial inflorescences

  • Hiroshi S. IshiiEmail author
  • Yuimi Hirabayashi
  • Gaku Kudo
Plant-Animal Interactions - Original Paper


Pollen dispersal by pollinators is governed by the extent to which diverse effects on pollinator behaviour act independently or augment or moderate each other. Using artificial inflorescences, we assessed the behavioural responses of bumble bees to inflorescence architecture (raceme, panicle, and umbel), inflorescence size (7 or 13 flowers), inter-inflorescence distance and the proportion of empty flowers per inflorescence. The advantage of large inflorescences in terms of attractiveness was larger for racemes and umbels than for panicles, whereas the effect of inter-inflorescence distance on the number of successive probes was smaller for racemes than for panicles and umbels. The number of flowers probed per visit increased almost proportionally with display size when fewer flowers were empty, whereas the number increased less when many flowers were empty. Our results suggest that display size and the spatial arrangement of flowers and nectar within inflorescences can contribute to efficient pollination by affecting pollinator behaviour interactively.


Artificial flower Bombus Nectar Pollinator 



We thank L.D. Harder for his critical comments on the manuscript and assistance with statistical analysis. In addition, two anonymous reviewers provided valuable comments on the manuscript. We also thank the member of Regional Ecosystems in Hokkaido University for building the flight cage, and A.M. Ishii for collecting data. This research was funded by a fellowship of the Japan Society for the promotion of Science to H.S.I. (no. 0124) and a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology, Japan to G.K. (no. 15370006). The experiment complies with the laws of Japan, the country in which it was performed.


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Hiroshi S. Ishii
    • 1
    Email author
  • Yuimi Hirabayashi
    • 2
  • Gaku Kudo
    • 3
  1. 1.Department of Ecosystem Studies, Institute of Agricultural and Life SciencesThe University of TokyoTokyoJapan
  2. 2.Obihiro Centennial MuseumObihiroJapan
  3. 3.Graduate School of Environmental Earth ScienceHokkaido UniversitySapporoJapan

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