, Volume 116, Issue 4, pp 519–527

Nectar robbing in Ipomopsis aggregata : effects on pollinator behavior and plant fitness

  • Rebecca E. Irwin
  • Alison K. Brody

DOI: 10.1007/s004420050617

Cite this article as:
Irwin, R. & Brody, A. Oecologia (1998) 116: 519. doi:10.1007/s004420050617


Hummingbirds foraging in alpine meadows of central Colorado, United States, face a heterogeneous distribution of nectar rewards. This study investigated how variability in nectar resources caused by nectar-robbing bumblebees affected the foraging behavior of hummingbird pollinators and, subsequently, the reproductive success of a host plant (Ipomopsis aggregata). We presented hummingbirds with experimental arrays of I. aggregata and measured hummingbird foraging behavior as a function of known levels of nectar robbing. Hummingbirds visited significantly fewer plants with heavy nectar robbing (over 80% of available flowers robbed) and visited fewer flowers on those plants. These changes in hummingbird foraging behavior resulted in decreased percent fruit set as well as decreased total seed set in heavily robbed plants. These results indicate that hummingbird avoidance of nectar-robbed plants and flowers reduces plant fitness components. In addition, our results suggest that the mutualisms between pollinators and host plants may be affected by other species, such as nectar robbers.

Key words Bumblebees Cheating behavior Hummingbirds Ipomopsis aggregata Nectar robbery 

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Rebecca E. Irwin
    • 1
  • Alison K. Brody
    • 1
  1. 1.Department of Biology, University of Vermont, Burlington, VT 05405, USA e-mail: rirwin@zoo.uvm.edu, Fax: +1-802-6562914US
  2. 2.Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USAUS

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