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Full-Text Articles in Life Sciences

A Bt Transgene Reduces Herbivory And Enhances Fecundity In Wild Sunflowers, A. A. Snow, Diana Pilson, L. H. Rieseberg, M. J. Paulsen, N. Pleskac, M. R. Reagon, D. E. Wolf, S. M. Selbo Apr 2003

A Bt Transgene Reduces Herbivory And Enhances Fecundity In Wild Sunflowers, A. A. Snow, Diana Pilson, L. H. Rieseberg, M. J. Paulsen, N. Pleskac, M. R. Reagon, D. E. Wolf, S. M. Selbo

Diana Pilson Publications

Gene flow from transgenic crops can introduce novel traits into related species, but the ecological importance of this process is unknown. Here, we report the first empirical evidence that wild plants can benefit from a bacterial transgene under uncaged, natural conditions. Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States. We studied a crop-developed Bacillus thuringiensis (Bt) transgene, cry1Ac, in backcrossed wild sunflower populations. Lepidopteran damage on transgenic plants was strongly reduced relative to control plants at our two study sites, while damage …


Compensation For Herbivory In Wild Sunflower: Response To Simulated Damage By The Head-Clipping Weevil, Diana Pilson, Karin L. Decker Jan 2002

Compensation For Herbivory In Wild Sunflower: Response To Simulated Damage By The Head-Clipping Weevil, Diana Pilson, Karin L. Decker

Diana Pilson Publications

Herbivore damage is generally detrimental to plant fitness, and the evolutionary response of plant populations to damage can involve either increased resistance or increased tolerance. While characters that contribute to resistance, such as secondary chemicals and trichomes, are relatively well understood, characters that contribute to a plant’s ability to tolerate damage have received much less attention. Using Helianthus annuus (wild sunflower) and simulated damage of Haplorhynchites aeneus (head-clipping weevil) as a model system, we examined morphological characters and developmental processes that contribute to compensatory ability. We performed a factorial experiment that included three levels of damage (none, the first two, …


Plant Hybrid Zones And Insect Host Range Expansion, Diana Pilson Jan 1999

Plant Hybrid Zones And Insect Host Range Expansion, Diana Pilson

Diana Pilson Publications

The hybrid bridge hypothesis suggests that plant hybrids ‘‘bridge’’ the genetic gap between actual and potential host species, and that, for this reason, herbivorous insects are more likely to evolve an expanded host range in the presence of hybrids. While intuitively appealing, the hypothesis has two implicit assumptions: that phenotypic gaps between potential hosts limit host range, and that characters controlling host use are additively inherited in plant hybrids. Evaluation of these assumptions suggests that operation of the hybrid bridge hypothesis is relatively uncommon. In addition, the hypothesis has not been well integrated into existing theoretical and empirical work on …