Author
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Greenstone, Matthew |
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Submitted to: Bulletin of Entomological Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/21/2005 Publication Date: 1/2/2006 Citation: Greenstone, M.H. 2006. A review of molecular methods for assessing insect parasitism. Bulletin of Entomological Research. 96:1-13. Interpretive Summary: Parasitioids are insects, mainly tiny flies and wasps, whose young develop in or upon the bodies of other insects. They destroy billions of pest insects annually in crops worldwide and are key players in insect pest management by biological control. However their use is hampered by difficulties in identifying closely related species due to their small size and very similar appearance in many cases. This research reviewed the literature of methods that entomologists have employed to detect and distinguish biological molecules, mainly proteins and nucleic acids, to detect parasitoids and tell them apart. The review found that two of four methods were either too unreliable or too costly to be of general use, while the other two, enzyme analysis and DNA fingerprinting are both reliable and fingerprinting is very sensitive, allowing detection of the parasitoid at a very early stage. This research will be used by entomologists to choose the most appropriate technology to study interactions between parasitoids and insect pests, and thereby contribute to more effective insect pest management by helping them to identify the most effective parasitoids. Technical Abstract: Determining insect parasitism rates is problematic due to the small size and lack of useful distinguishing morphological characters of many parasitoid taxa. To solve this problem, entomologists have employed one of four general methods to detect parasitoid protein or nucleic acid markers: serological assay; RAPD-PCR; allozyme electrophoresis; or specific PCR. Serological methods, especially with monoclonal antibodies, are unrivaled for specificity, enabling discrimination at the stage as well as species level. However they have not found favor with many workers, possibly due to complexity and expense. RAPD-PCR has been widely used, but can only be recommended for restricted applications because of its poor reproducibility. Allozyme electrophoresis provides reproducible detection and discrimination of closely related species. Specific-PCR and is highly specific and reproducible, and also has the shortest latency for detection, usually 24 hours or less after parasitization. I use the substantial existing literatures on allozyme electrophoresis and specific PCR to support recommendations on what are apt to be fruitful enzyme systems or genomic regions for detecting and discriminating parasitoids in untried parasitoid host assemblages. |
