Distance and height of attraction by walking and flying conspecifics to traps with simultaneous use of the aggregation pheromones from Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (F.)...

Authors: DISSANAYAKA, D.M.S. - Rajarata University Of Sri Lanka; SAMMANI, A.M. - Rajarata University Of Sri Lanka; WIJAYARATNE, L.K. - Rajarata University Of Sri Lanka; BAMUNUARACHCHIGE, T. - Rajarata University Of Sri Lanka; Morrison, William - Rob

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2020
Publication Date: 9/19/2020
Citation: Dissanayaka, D.K., Sammani, A.P., Wijayaratne, L.W., Bamunuarachchige, T.C., Morrison III, W.R. 2020. Distance and height of attraction by walking and flying conspecifics to traps with simultaneous use of the aggregation pheromones from Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (F.).... Journal of Stored Products Research. 89: 101705. https://doi.org/10.1016/j.jspr.2020.101705.
DOI: https://doi.org/10.1016/j.jspr.2020.101705

Interpretive Summary: In deploying pheromone-baited traps around food facilities, stakeholders have often voiced a concern over whether more insects would be attracted from a greater distance than would otherwise have come to the facility. Allaying this concern will speed adoption of pheromone-based monitoring programs, and help protect the US food supply after harvest by delivering accurate information about which insects are present, and whether additional tactics are required. In this study, we evaluated the distance and height of attraction by walking and/or flying stored product beetles to traps with pheromones for both the red flour beetle and lesser grain borer. We used commercially available and widely used pitfall traps (Storgard Dome traps) and flight traps (e.g. MicroDot traps). In a warehouse setting, we found that the maximum trap capture for red flour beetle and lesser grain borer was when traps were placed up to 30 cm, and between 30-60 cm away from adults of each species, respectively. Captures of walking insects from farther distances gradually fell off for red flour beetle, while no lesser grain beetles were captured by traps placed 120 cm away. Flying lesser grain borer were optimally captured in traps deployed no more than 10 m above the ground, and none were captured when they were deployed higher than 40 cm above. Together, this delivers important behavioral information about distance and height of attraction by two cosmopolitan and destructive stored product insects, which may inform trapping and monitoring programs at food facilities.

Technical Abstract: Adults of Tribolium castaneum and Rhyzopertha dominica produce the aggregation pheromones 4-8 DMD and DL-1/DL-2, respectively. The common practice is that these pheromones are used independently. While the adults of both species are mobile, R. dominica are strong fliers capable of moving across different habitats, but weak walkers, while T. castaneum are weak fliers, but strong walkers. Monitoring efficiency for both species using traps with simultaneous use of the two pheromones has not been adequately studied. Therefore, objectives of this research were to evaluate distance and height of attraction to traps with the simultaneous use of both pheromones on trapping T. castaneum and R. dominica adults. In the first experiment, the two pheromones were deployed together in separate septa inside a commercial pitfall trap (Dome® Trap). A total of 20 one-month-old T. castaneum and R. dominica adults were released every 30 cm from 30–150 cm away from the pheromone trap. The adults trapped were recorded at 4 and 24 h following their release. Adults of both species released were captured in higher percentages at 24 hours than 4 hours. The maximum trap capture was at 30 cm for T. castaneum and between 30–60 cm for R. dominica. The second experiment was conducted inside a cage covered with mesh. One MicroDot trap with two rubber septa containing DL-1 and DL-2 was placed at roughly 5 cm intervals from 3-50 cm from the bottom of the cage and the adult R. dominica were released at the bottom. After 24 h, flying R. dominica adults were captured in progressively lower percentages as trap height increased up to 40 cm above the bottom of the cage. Trap heights above 10 cm exhibited decreased trap capture of R. dominica compared to those at 3 cm. We conclude that the use of both aggregation pheromones facilitates trapping of walking T. castaneum and R. dominica optimally at 30–60 cm from a trap, while traps above 10 cm show decreased captures of flying R. dominica.