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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICALLY-BASED PEST MANAGEMENT STRATEGIES FOR WESTERN COTTON Title: Identifying the predator complex of Homalodisca vitripennis (Hemiptera: Cicadellidae): A comparative study of the efficacy of an ELISA and PCR gut content assay

Authors
item Fournier, Valerie - LAVAL UNIV, CANADA
item Hagler, James
item Daane, Kent - UC BERKELEY, CA
item DE Leon, Jesus
item Groves, Russell - U OF WI, MADISON, WI

Submitted to: Oecologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 4, 2008
Publication Date: July 10, 2008
Citation: Fournier, V., Hagler, J.R., Daane, K., De Leon, J.H., Groves, R. 2008. Identifying the predator complex of Homalodisca vitripennis (Hemiptera: Cicadellidae): A comparative study of the efficacy of an ELISA and PCR gut content assay. Oecologia. 157: 629-640

Interpretive Summary: The two most popular gut content assays are immunoassays employing pest-specific monoclonal antibodies (MAb) and polymerase chain reaction (PCR) assays employing pest-specific DNA. We conducted a study that simultaneously used both methods to identify predators of the glassy-winged sharpshooter (GWSS). A total of 1,231 arthropod predators, representing 30 taxa, were collected from urban landscapes in central California and assayed first by enzyme-linked immunosorbent assay (ELISA) using a GWSS-egg specific MAb and then by PCR using a GWSS-specific DNA marker. The gut content analyses revealed that GWSS remains were present in 15.5 percent of the predators examined; with 18 percent of the spiders and 11 percent of the insect predators testing positive, respectively. Moreover, a comparison of the two assays indicated that they were not equally effective at detecting GWSS remains in predator guts. The advantages of combining the attributes of both types of assays to more precisely assess field predation and the pros and cons of each assay for mass-screening predators are discussed.

Technical Abstract: A growing number of ecologists are using molecular gut content assays to qualitatively measure predation. The two most popular gut content assays are immunoassays employing pest-specific monoclonal antibodies (MAb) and polymerase chain reaction (PCR) assays employing pest-specific DNA. Here we present results from the first study to simultaneously use both methods to identify predators of the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae). A total of 1,231 arthropod predators, representing 30 taxa, were collected from urban landscapes in central California and assayed first by enzyme-linked immunosorbent assay (ELISA) using a GWSS-egg specific MAb and then by PCR using a GWSS-specific DNA marker that amplifies a 197 base pair fragment of its cytochrome oxidase gene (subunit I). The gut content analyses revealed that GWSS remains were present in 15.5% of the predators examined; with 18% of the spiders and 11% of the insect predators testing positive, respectively. Common spider predators included members from the Salticidae, Clubionidae, Anyphaenidae, Miturgidae, and Corinnidae families. Common insect predators included lacewings (Neuroptera: Chrysopidae), praying mantis (Mantodea: Mantidae), ants (Hymenoptera: Formicidae), assassin bugs (Hemiptera: Reduviidae), and damsel bugs (Hemiptera: Nabidae). Comparison of the two assays indicated that they were not equally effective at detecting GWSS remains in predator guts. The advantages of combining the attributes of both types of assays to more precisely assess field predation and the pros and cons of each assay for mass-screening predators are discussed.

Last Modified: 12/20/2014
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