ECOLOGY, SAMPLING, AND MODELING OF INSECT PESTS OF STORED GRAIN, PROCESSING FACILITIES, AND WAREHOUSES
Location: Stored Product Insect Research Unit
Title: Horizontal transfer of methoprene in Tribolium castaneum
Submitted to: Stored Products Protection International Working Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 18, 2010
Publication Date: December 9, 2010
Citation: Tucker, A.M., Campbell, J.F., Arthur, F.H., Zhu, K. 2010. Horizontal transfer of methoprene in Tribolium castaneum. In: Stored Products Protection International Working Conference Proceedings, June 27 - July 2, 2010, Estoril, Portugal. p. 819-824.
Aerosol applications of reduced risk insecticides such as pyrethrins, pyrethroids, and insect growth regulators are becoming more commonly used to manage stored-product insects in food facilities. However, these applications have a limited ability to penetrate into hidden refugia, where the majority of the pest population is located. Horizontal transfer of insecticides could occur as individuals directly treated or exposed to treated surfaces move into hidden refugia and encounter untreated individuals. In this series of studies, the potential for horizontal transfer of methoprene from treated Tribolium castaneum, the red flour beetle, to untreated focal individuals was evaluated. Adding larvae, pupae, or adults treated with methoprene to flour patches with untreated T. castaneum larvae, resulted in increased pupal and adult deformities and higher numbers of dead focal individuals, which suggests the potential for this mechanism. The transfer mechanism might be flour substrate contamination, transfer during contact of individuals, and/or cannibalism of individuals exposed to insecticides. Experiments focused on isolating the impact of contact and cannibalism on horizontal transfer did not detect a significant increase in mortality. Experiments focused on flour substrate contamination resulted in decreased adult emergence as well as lower survival, and higher rates of deformities. These findings suggest that substrate contamination is the more likely mechanism for horizontal transfer, and although horizontal transfer can occur, the impact of this process on populations needs further evaluation.