Response of ground beetle (Coleoptera: Carabidae) field populations to four years of Lepidoptera-specific Bt corn production.
Pitfall traps were used to monitor populations of ground beetles (Coleoptera: Carabidae) in plots of corn grown in continuous cultivation during a 4-yr period (2000-2003). Treatments included transgenic corn expressing a Bt Cry protein with efficacy specific against Lepidoptera (Bt), conventional corn grown with insecticide application (I), and the same conventional cultivar grown without insecticide application (NI). Mixed-model analyses of variance were performed on pitfall captures of beetles combined across weeks to give seasonal sums. Effects of corn treatment were not detected (P > 0.05) on total beetle abundance or species richness in any year. Effects of corn treatment on individual taxa were detected (P < 0.05) for 3 of the 39 species-by-year combinations examined. Effects of near significance (P < 0.08) were detected for an additional two species. In 2001, captures of Amara farcta Leconte and Harpalus amputatus Say were lower in Bt plots than in I or NI plots. In 2003, captures of Amara apricaria (Paykull) and Amara carinata (Leconte) were higher in Bt plots than in I or NI plots. Also in 2003, captures of Poecilus scitulus Leconte were higher in I plots than in Bt or NI plots. These patterns were not repeated among years. Results of this study indicate that cultivation of Lepidoptera-specific Bt corn in southern Alberta does not appreciably affect ground beetle populations.
Floate
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KD
Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 1st Ave. S., Lethbridge, AB, Canada T1J 4B1. floatek@agr.gc.ca
Cárcamo
H A
HA
Blackshaw
R E
RE
Postman
B
B
Bourassa
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S
D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism; D044822:Biodiversity; D001517:Coleoptera; D004731:Endotoxins / Q000378:metabolism; D006460:Hemolysin Proteins / Q000378:metabolism; D007306:Insecticides; D007915:Lepidoptera; D030821:Plants, Genetically Modified; D011156:Population Density; D003313:Zea mays / Q000235:genetics / Q000378:metabolism*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis