|Sears Wichmann, Sheila|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2008
Publication Date: 4/1/2009
Citation: Roehrdanz, R.L., Olson, D.L., Fauske, G.M., Bourchier, R.S., Cortilet, A.B., Sears, S. 2009. New DNA markers reveal presence of Aphthona species (Coleoptera: Chrysomelidae) believed to have failed to establish after release into leafy spurge. Biological Control. 49(1):1-5. Interpretive Summary: Several species of flea beetles have been imported into North America to combat the prolific rangeland weed, leafy spurge. Larval stages of these beetles cannot be separated into species. Likewise, the species with brown adults are very difficult to reliably identify. We have developed a DNA based system that can separate the five species of leafy spurge flea beetles that are currently established in North America. The DNA markers provide a means to determine which species is the most effective biological control agent at different locations. The markers have been used to discover groups of two of the species that were thought to have been extirpated from North Dakota.
Technical Abstract: Six species of Aphthona flea beetles from Europe have been introduced in North America for the purpose of controlling a noxious weed, leafy spurge (Euphorbia esula). In the years following the releases, five of the species have been recorded as being established at various locations. There is no evidence that the sixth species ever became established. A molecular marker key that can identify the DNA of the five established species is described. The key relies on restriction site differences found in PCR amplicons of a portion of the mitochondrial cytochrome oxidase I gene. Three restriction enzymes are required to separate the immature specimens which are not visually separable. Adults which can be quickly separated into the two black species and three brown species require only two restriction enzymes to resolve the species. Many of the original releases and relocations of the flea beetles used populations containing mixed species that were often not thoroughly characterized as to species. The markers showed the presence of two Aphthona species in North Dakota that were believed to have been absent from the state for the past decade. Without the marker assay these populations would probably have been overlooked.