Monday, 18 November 2002
D0054

This presentation is part of : Student Competition Display Presentations, Subsection Ca. Biological Control

Molecular approaches used to augment the classical biological control of Senecio jacobaea with the flea beetle Longitarsus jacobaeae

Kenneth P. Puliafico1, Jeffrey Littlefield1, and Deanna Nash2. (1) Montana State University, Entomology, 333 Leon Johnson Hall, Bozeman, MT, (2) Montana State University, Plant Sciences & Plant Pathology, 330 Leon Johnson Hall, Bozeman, MT

Longitarsus jacobaeae is considered the most important biological control agent for the suppression of tansy ragwort (Senecio jacobaea) in the maritime areas of the Pacific Northwest.  Our research focused on the Swiss biotype of L. jacobaeae that is pre-adapted to the continental climate of Montana.  During the search for the cold hardy biotype of L. jacobaeae two molecular techniques were added to the classical biological control research regime.  Mitochondrial DNA sequencing was used to determine the taxonomic relation of populations of Longitarsus flea beetles.  While a second technique for disease screening was conducted with Wolbachia specific PCR primers. 

Comparisons between several European beetle populations and those already present in North America were made using mitochondrial DNA sequencing.  Analysis focused on a combination of highly variable and conservative gene regions that are found in the cytochrome oxidase I and II genes to determine genetic variability within and between populations.  Direct comparisons in mtDNA sequences were also made between L. jacobaeae and its sister species L. flavicornis.  An out-group was chosen from the closely related Aphthona genus to elucidate the differences between Longitarus species.

Disease screening for the Wolbachia bacteria was conducted using specific PCR primers developed by S.L. O'Neill et al.  We investigated the feasibility of the technique as a pre-release screening tool by extracting DNA from the hind leg of live beetles.  DNA extracted for the purpose of taxonomic determination was also used to screen all the beetle populations to establish the degree of prevalence of Wolbachia bacterial infections. 



Species 1: Coleoptera Chrysomelidae Longitarsus jacobaeae (tansy ragwort flea beetle)
Species 2: Asterales Asteraceae Senecio jacobaea (tansy ragwort, stinking willy)
Keywords: mtDNA, Wolbachia

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