Different effects of variation in Xanthium strumarium L. (Compositae) on two insect seed predators
- 1) Department of Ecology and Evolution, State University of New York at Stony Brook, 11794, Stony Brook, NY, USA
To determine the relative importance of variation in several plant characters on susceptibility to herbivores, we examined patterns of seed predation by two monophagous insect species and patterns of variation in ten populations of the cocklebur, Xanthium strumarium. Multiple regression analysis disclosed that one seed predator was most influenced by plant chemical variation, the other was significantly influenced by both chemical and morphological variation, but variation in yet another character, general burr size, was most important in conferring resistance to both insects simultaneously. The plant populations differed most in this character. Although many of the plant characters were correlated with each other, those important in determining susceptibility to each insect species were uncorrelated and independent of those conferring resistance to both insects simultaneously. These results imply that ecological similar herbivores may be influenced by different aspects of plant variation, and that predictions of evolutionary responses of local plant populations to herbivory may require knowledge of the structure of local herbivore communities and the dynamics of their establishment.
- 1 - sciences appliquees, technologies et medecines
- 2 - sciences biologiques et medicales
- 3 - sciences biologiques fondamentales et appliquees. psychologie
- 4 - phytopathologie. zoologie agricole. protection des cultures et des forets
- 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Ecology, Evolution, Behavior and Systematics