Monday, December 11, 2006 - 8:47 AM

Effects of Cry34/35 Bt-corn pollen on non-target ground beetles

Miles Lepping,, Galen P. Dively,, Paula Shrewsbury,, and Shannon Seopaul, University of Maryland, 4112 Plant Sciences Bldg, Dept. of Entomology, College Park, MD

A laboratory study examined effects of continuous exposure to beetle-active (Cry34/35) transgenic Bt-corn pollen by adults of the minute ground beetle, Elaphropus xanthopus (Dejean), and the rove beetle, Strigota ambigua (Erichson). Adult beetles were fed pollen from either Cry34/35 or non-Bt isoline plants, at limited or unlimited availability levels. Toxic control treatments included pollen laced with dilute pyrethroid insecticide (20 K dilution). Hazard assessment endpoints included longevity and sub-lethal behavioral measures (grooming, searching/foraging, pollen consumption, and frass deposition). Elaphropus xanthopus longevity under unlimited Cry34/35 pollen availability was 58.7 8.1 d, and 73.4 5.8 d for non-Bt pollen. Strigota ambigua longevity under unlimited Cry34/35 pollen availability was 30.2 8.1 d, and 55.4 11.7 for non-Bt pollen. No negative effects of the transgenic pollen were detected for either beetle. Conversely, detrimental effects of pyrethroid-laced pollen exposure included decreased searching/foraging and frass deposition for E. xanthopus, and decreased longevity and increased grooming for S. ambigua. These findings suggest that field exposure to Cry34/35 proteins by way of pollen would not be expected to pose significant hazard to either E. xanthopus or S. ambigua adult performance. Additionally, results suggest that increasing pollen availability increases longevity for both species.

Species 1: Coleoptera Carabidae Elaphropus xanthopus
Species 2: Coleoptera Staphylinidae Strigota ambigua