Author
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Lundgren, Jonathan |
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Submitted to: American Entomologist
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/3/2005 Publication Date: 11/1/2005 Citation: Lundgren, J.G. 2005. Ground beetles as weed control agents: effects of farm management on granivory. American Entomologist. 51(4): 224-226. Interpretive Summary: This short article describes suitability of seeds for two granivorous ground beetles in the laboratory and a field-scale study on farm management intensity on seed predation of weeds. Under no-choice condition, the relative consumption rate by Anisodactylus sanctaecrucis and Harpalus pensylvanicus of giant ragweed, giant foxtail, broccoli, alfalfa, crabgrass, velvetleaf, redroot pigweed, ivyleaf morning glory, and common lambsquarters were recorded. For A. sanctaecrucis, the pigweed, foxtail, and ragweed were not offered, but red fescue was. Weekly seed removal rates from Petri dishes of the above-listed weeds were monitored over three weeks in three different systems. The systems were vegetable, cash grain, and pasture, and were intended to mimic strategies used by farmers to transition to organic production. Laboratory tests revealed that lambsquarters seed was most acceptable to both beetle species. However, the other seed species varied in their acceptability between the two beetles. In the field, farm management intensity influenced seed removal rates, with highest granivory occurring in pasture systems. Also, granivorous insects had a clear preference for certain seed species under field conditions. Technical Abstract: Here, I describe the suitability of seeds for two granivorous ground beetles in the laboratory and a field-scale study on farm management intensity on seed predation of weeds. Under no-choice condition, the relative consumption rate by Anisodactylus sanctaecrucis and Harpalus pensylvanicus of giant ragweed, giant foxtail, broccoli, alfalfa, crabgrass, velvetleaf, redroot pigweed, ivyleaf morning glory, and common lambsquarters were recorded over a 48 h period. For A. sanctaecrucis, the pigweed, foxtail, and ragweed were not offered, but red fescue was. Weekly seed removal rates from Petri dishes of the above-listed weeds were monitored over three weeks in three different systems. The systems were vegetable, cash grain, and pasture, and were intended to mimic strategies used by farmers to transition to organic production. Laboratory tests revealed that lambsquarters seed was most acceptable to both beetle species. However, the other seed species varied in their acceptability between the two beetles. In the field, farm management intensity influenced seed removal rates, with highest granivory occurring in pasture systems. Also, granivorous insects had a clear preference for certain seed species under field conditions. |
