Author
French, Bryan | |
Chandler, Laurence - Larry | |
Ellsbury, Michael | |
FULLER, BILLY - SOUTH DAKOTA STATE UNIV | |
West, Mark |
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/23/2004 Publication Date: 6/1/2004 Citation: French, B.W., Chandler, L.D., Ellsbury, M.M., Fuller, B.W., West, M. 2004. Ground beetle (Coleoptera: chrysomelidae) assemblages in a transgenic corn-soybean cropping system. Environmental Entomology 33(3): 554-563. Interpretive Summary: Ground beetles often prey on crop pests. Ground beetle abundances and assemblages often vary among cropping systems and pest management practices. We used pitfall traps arranged in transects to study ground beetle assemblages in large field-scale corn-soybean cropping systems for 3 years. The transgenic corn expressed the Cry1Ab protein targeting lepidopteran pests. Three of 57 species collected accounted for 81% of all individuals captured. Six other species accounted for an additional 14% of all beetles captured. Most ground beetles were captured in the cornfields; however, many also were captured in soybean fields. Ground beetles were most abundant at field edges, but also abundant within field centers. Multivariate analysis was used to arrange ground beetles along environmental gradients. Years 2001 and 2002 were the primary variables separating assemblages of ground beetles along the 1st axis. The 2nd axis further separated the 2000 assemblage of ground beetles. Ground beetles were classified with respect to crop type and distance into the fields along axes 1 and 2 of a partial canonical correspondence analysis. Based on this analysis, ground beetles occupying the cornfields were separated from those occupying soybean fields along the 1st axis. The 2nd axis separated beetles occupying the field borders from field interiors. Because of their high abundances, continuous seasonal activity, predatory nature, and ability to occupy field centers, ground beetles are good candidates for biological control of corn and soybean pests. Technical Abstract: Ground beetles often prey on crop pests, and their abundances and assemblages vary among cropping systems and pest management practices. We used pitfall traps arranged in transects to study ground beetle assemblages in a large field-scale Bt corn ' soybean cropping system for 3 years. The transgenic corn expressed the Cry1Ab protein targeting lepidopteran pests. Three of the 57 ground beetle species collected accounted for 81% of all individuals captured. Six other species accounted for an additional 14% of all beetles captured. Most ground beetles were captured in the cornfields, however, substantial numbers were captured in soybean fields. Ground beetles were most abundant at field edges, but many were captured within field centers. Canonical correspondence analysis was used to arrange ground beetles along environmental gradients. Years 2001 and 2002 were the primary variables separating assemblages of ground beetles along the 1st canonical axis. The 2nd canonical axis further separated the 2000 assemblage of ground beetles. With the effects of year and field removed, ground beetles were classified with respect to crop association and distance into the fields along axes 1 and 2 of a partial canonical correspondence analysis. Based on this analysis, ground beetles occupying the cornfields were separated from those occupying soybean fields along the 1st canonical axis. The 2nd canonical axis separated beetles occupying the field borders from field interiors. Because of their high abundances, continuous seasonal activity, predatory nature, and ability to occupy field centers, ground beetles are good candidates for biological control of corn and soybean pests. |