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Full-Text Articles in Ecology and Evolutionary Biology

Invasive Insect Abundance Varies Across The Biogeographic Distribution Of A Native Host Plant, Tatyana A. Rand, Svata M. Louda Jan 2006

Invasive Insect Abundance Varies Across The Biogeographic Distribution Of A Native Host Plant, Tatyana A. Rand, Svata M. Louda

Svata M. Louda Publications

Studies of biogeographic variation in species abundances are fundamental to understanding and predicting the impacts of invasive exotic species. We quantified the abundance of the introduced and now invasive biocontrol weevil, Rhinocyllus conicus, on a newly adopted native host plant, Cirsium canescens (Platte thistle), across the plant’s distributional range. We used regression and structural equation analyses to examine variation in weevil abundance at 92–108 sites over three years in relation to variation in abiotic and biotic parameters hypothesized to be important in insect or plant dynamics and distribution. We found that R. conicus now occurs throughout the majority of …


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, …


Herbivore Effect On Stature, Fruiting, And Leaf Dynamics Of A Native Crucifer, Svata M. Louda Jan 1984

Herbivore Effect On Stature, Fruiting, And Leaf Dynamics Of A Native Crucifer, Svata M. Louda

Svata M. Louda Publications

The impact of a native, leaf-feeding chrysomelid beetle (Phaedon sp. nr. oviformis) on bittercress (Cardamine cordifolia: Cruciferae), was evaluated in an exclusion experiment. Multivariate statistical analysis showed a significant increase in plant performance in the rotenone exclusion compared to performance in the paired control treatment. Plant response to the reduction of herbivory was a complicated, interrelated syndrome of changes. When insects were excluded, the amount of missing leaf area decreased significantly (3.6-fold; 3.2-0.9 cm2 per plant), and the total leaf area increased 5.7-fold (12.9-73.4 cm2 per plant). Plant height (5.7-20.3 cm) and fruit production …