, Volume 166, Issue 3, pp 681–692 | Cite as

Additive effects of herbivory, nectar robbing and seed predation on male and female fitness estimates of the host plant Ipomopsis aggregata

  • Rebecca E. Irwin
  • Alison K. Brody
Plant-Animal interactions - Original Paper


Many antagonistic species attack plants and consume specific plant parts. Understanding how these antagonists affect plant fitness individually and in combination is an important research focus in ecology and evolution. We examined the individual and combined effects of herbivory, nectar robbing, and pre-dispersal seed predation on male and female estimates of fitness in the host plant Ipomopsis aggregata. By examining the effects of antagonists on plant traits, we were able to tease apart the direct consumptive effects of antagonists versus the indirect effects mediated through changes in traits important to pollination. In a three-way factorial field experiment, we manipulated herbivory, nectar robbing, and seed predation. Herbivory and seed predation reduced some male and female fitness estimates, whereas plants tolerated the effects of robbing. The effects of herbivory, robbing, and seed predation were primarily additive, and we found little evidence for non-additive effects of multiple antagonists on plant reproduction. Herbivory affected plant reproduction through both direct consumptive effects and indirectly through changes in traits important to pollination (i.e., nectar and phenological traits). Conversely, seed predators primarily had direct consumptive effects on plants. Our results suggest that the effects of multiple antagonists on estimates of plant fitness can be additive, and investigating which traits respond to damage can provide insight into how antagonists shape plant performance.


Herbivory Ipomopsis aggregata Nectar robbing Nectar Phenology Pollination Pollen deposition Seed predation Trait-based approach 



We thank L. Burkle, B. Degasparis, E. Deliso, K. Fitzgerald, E. Henry, A. Rastogi, K. Ritter, and A. Schuett for help in the field and lab. R. Rosetti from the Dartmouth Women in Science Program helped count pollen for the male function estimates. A. Carper, G. Clarke, J. Evans, Z. Gezon, N. Gotelli, E. Hart, J. Manson, C. Orians, R. Petipas, R. Schaeffer, and two anonymous reviewers provided valuable comments on the manuscript. Field and lab work were funded by the National Science Foundation (NSF) DEB-9806501, and supplies and lab assistance for pollen counting were provided by NSF DEB-0455348 and the Dartmouth Women in Science Program.


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Department of BiologyDartmouth CollegeHanoverUSA
  2. 2.Rocky Mountain Biological LabCrested ButteUSA
  3. 3.Department of BiologyUniversity of VermontBurlingtonUSA

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