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United States Department of Agriculture

Agricultural Research Service

Research Project: INSECT ECOLOGY AND SUSTAINABLE SYSTEMS FOR INSECT PEST MANAGEMENT IN THE SOUTHEASTERN REGION

Location: Crop Protection and Management Research

Title: Threshold detection of boar taint chemicals using parasitic wasps

Authors
item Olson, Dawn
item Wackers, Felix -
item Haugen, John-Erik -

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 21, 2012
Publication Date: October 12, 2012
Citation: Olson, D.M., Wackers, F., Haugen, J. 2012. Threshold detection of boar taint chemicals using parasitic wasps. Journal of Food Science. 77:356-361.

Interpretive Summary: A particular need in the use of a biosensor for food quality assessment is the organism’s ability to detect and report threshold concentrations of food contaminants. We tested a parasitoid, Microplitis croceipes’ ability to learn and respond to particular concentrations of the compounds, skatole and androstenone. We also tested the wasps’ ability to discriminate between known concentrations of indole, skatole and androstenone in near-real life scenarios. We then tested M. croceipes’ response to absolute versus proportions of concentrations in mixtures, and to a range of concentrations of a compound. We found that M. croceipes’ learning and responses are both concentration and compound dependent, and they responded to actual concentration rather than to the proportion of compounds in a mixture. Through positive and negative training, these wasps are also able to respond to a range of concentrations at desired threshold and higher levels. The promise of the use of this species as a biosensor in real applications is high.

Technical Abstract: Surgical castration has been long used to prevent consumers from experiencing taint in meat from male pigs, which is a large problem in the pig husbandry industry. Due to obvious animal welfare issues, the EU now wants an alternative for castration. Thus there is an urgent need for novel methods of boar taint detection. We tested Microplitis croceipes’ ability to learn and respond to particular concentrations of the compounds, skatole and androstenone. We also tested the wasps’ ability to discriminate between known concentrations of indole, skatole and androstenone in real boar fat samples at room temperature. We then tested M. croceipes’ response to absolute versus proportions of concentrations in mixtures, and to a range of concentrations of a compound. We found that M. croceipes’ learning and responses are concentration and compound dependent. Wasps trained to a particular concentration of skatole will respond to the training and the 10× lower concentration, but not to the 10× higher concentration. Contrarily, for indole wasps respond to the training compound and the 10× higher but not the 10× lower concentration. Wasps trained to androstenone only respond to the training concentration when concentrations are <10'g/ml. M. croceipes also reported the low, medium and high concentrations of indole, skatole and androstenone in boar fat at room temperature, and they responded to actual concentration rather than to the proportion of compounds in a mixture. Through positive and negative training, these wasps are also able to respond to a range of concentrations at desired threshold and higher levels.

Last Modified: 7/25/2014
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