Oecologia

, Volume 135, Issue 4, pp 576–582 | Cite as

Invasive Argentine ants (Linepithema humile) do not replace native ants as seed dispersers of Dendromecon rigida (Papaveraceae) in California, USA

  • Shanna E. Carney
  • M. Brooke Byerley
  • David A. Holway
Plant Animal Interactions

Abstract

We investigated the indirect effects of Argentine ant (Linepithema humile) invasions on patterns of seed dispersal and predation in the myrmecochorous tree poppy Dendromecon rigida in coastal San Diego County, California. Significantly more seeds were removed from ant-accessible seed stations at sites numerically dominated by a common harvester ant (Pogonomyrmex subnitidus), a native disperser of these seeds and a species sensitive to displacement by L. humile, than from those stations at sites where L. humile was in the majority. Predation of seeds was high, but variable, across sites, suggesting that reduced dispersal could result in increased seed predation in some habitats. Removal of elaiosomes did not affect the frequency with which predators removed seeds, but ants removed significantly more seeds with elaiosomes than without. In behavior trials, only P. subnitidus was able to carry seeds of Dendromecon rigida effectively. L. humile and a small native ant species, Dorymyrmex insanus, while displaying interest in the diaspores, were seldom able to carry whole seeds and, when they did, only carried them a few centimeters. Displacement of native harvester ants by L. humile appears to decrease the dispersal of Dendromecon rigida seeds and may be increasing loss of seeds due to predation.

Keywords

Argentine ant Linepithema humile Dendromecon rigida Biological invasion Harvester ant Myrmecochory 

Notes

Acknowledgements

We wish to acknowledge the assistance of Linda Courter, Andrew Norton, Adam Henk, and the anonymous reviewers, whose helpful comments improved this manuscript. Additionally, Andrew Norton and James ZumBrunnen provided statistical assistance, and the Torrey Pines State Reserve staff granted us permission to work at this site. This work was supported by startup funds from Colorado State University (SEC) and USDA NRICGP 99-35302-8675 (DAH).

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Shanna E. Carney
    • 1
  • M. Brooke Byerley
    • 1
  • David A. Holway
    • 2
  1. 1.Department of BiologyColorado State UniversityFort CollinsUSA
  2. 2.Section of Ecology, Behavior, and Evolution, Division of Biological SciencesUniversity of CaliforniaSan Diego, La JollaUSA

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