Submitted to: Microbial Ecology International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 5/8/2006
Publication Date: N/A
Technical Abstract: Many insects harbor a robust complement of prokaryotes in their alimentary canals. These microorganisms may facilitate nutrient availability and utilization, detoxification of environmental toxins, or play other important roles in the insect's life history. Understanding insect-microorganism interactions is of interest because many insects are agricultural pests. We recently discovered that the excrement of the heteropterous insects, Lygus lineolaris and Euschistus servus, contains carbohydrates known to be associated with bacteria. Because these insects are serious agricultural pests, studies were conducted to characterize their microbial gut flora to evaluate the importance on insect biology. Identifying insect-microorganism interactions may provide novel approaches for insect control. We characterized the gut microflora of insects collected from a range of host plants from spring through fall. Additionally, we studied the effect of ingestion of a systemic insecticide on L. lineolaris gut microflora. Traditional culturing and molecular techniques were used to characterize and identify microbial communities, and high performance anion-exchange chromatography was used to identify carbohydrate production within specific microbial populations. In aerobic trials using nutrient, brain-heart infusion, sucrose and yeast-peptone agars, an average of 1.5x109, 2.9x109, 2.0x108 and 1.4x108 CFU/ml was obtained for L. lineolaris. An average of 7.5x107, 1.5x108, 8.9x107 and 7.9x107 CFU/ml was obtained for E. servus. Total microscopic counts averaged 2.6x108 cells/gut for L. lineolaris, and 6.2x109 cells/gut for E. servus. Molecular techniques, including 16S rRNA PCR, are being used to identify the microbial composition of the gut flora of these insects. To date, Rhodococcus, Erwinia, Pantoea and Photorhabdus species have been isolated.