Meeting Abstract

59.3  Sunday, Jan. 5 14:00  Orconectes rusticus growth and survival exposed to Bt corn LINN, M/L*; MOORE, P/A; Bowling Green State University; Bowling Green State University mdlinn@bgsu.edu

Bt crops are one of the mostly commonly utilized genetically modified crops. These Bt crops contain a gene that is derived from the bacteria Bacillus thuringiensis, producing the Cry1Ab toxin. Bt corn containing the Cry1Ab toxin is used throughout the midwest to control crop pests such as the European corn borer (Ostrinia nubilalis). Headwater streams in the corn-belt receive Bt corn detritus following the fall harvest, which is then consumed by a diverse community of stream invertebrates. The rusty crayfish (Orconectes rusticus) is a common invertebrate detritivore in these headwater streams and can be impacted by the consumption of Bt corn detritus. In order to assess the impact of Bt corn detritus on the health of this aquatic keystone species, rusty crayfish were exposed to 4 different types of detritus (Bt corn detritus, isogenic corn detritus, Bt corn + American sycamore (Platanus occidentalis) detritus, and isogenic corn + American sycamore detritus) for eight weeks. Both types of corn were grown under the identically controlled environmental conditions of a greenhouse and following senescence were tested for nutritional equality. Crayfish were housed in live streams with a water temperature of 12.8°C and identical photoperiod. Each week animals were removed to monitor survival and growth. Mortality was 31% higher in the Bt treatment than the isogenic treatment. Mixing Bt corn with American sycamore decreased mortality by 30%, while mixing isogenic corn with American sycamore increased mortality by 19%. After eight weeks of exposure there was no statistically significant difference in growth between Bt, isogenic, Bt mix, and isogenic mix treatments. These results suggest that the Bt and isogenic corn detritus have nutritional consequences that could increase mortality without influencing growth.