Ecological interactions between insect herbivores and their host plant in a weed biocontrol system
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Date
2003
Authors
Crowe, Michael
University of Lethbridge. Faculty of Arts and Science
Journal Title
Journal ISSN
Volume Title
Publisher
Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2003
Abstract
The role of interspecific competition as a regulating force in natural populations has been
controversial, especially for phytophagous insect communities. A series of manipulative
experiments using enclosure cages were conducted to evaluate the role of interspecific
competition between a weevil and a fly, two seed feeding agents released against spotted
knapweed in North America. The fly, an inferior biological control agent, was the
superior competitor. Consequences of the antagonistic interaction included reduced seed
destruction compared to if just the weevil was released on its own. The role of plant
phenology on insect herbivore density was also assessed. The implications of phenologyinduced
variation in insect density were evaluated with respect to competition between
the fly and the weevil and were found to be important. Hypotheses of four plantmediated
mechanisms of interspecific competition were also tested. Results support
resource preemption as a competitive mechanism.
Description
vii, 97 leaves ; 29 cm
Keywords
Insects as biological pest control agents -- Research , Nonmusic cds , Dissertations, Academic , Competition (Biology) , Beetles , Flies , Spotted knapweed -- Biological control -- Research