Submitted to: Bulletin of Insectology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/10/2008
Publication Date: 6/5/2008
Citation: Riddick, E.W., Brown, A.E., Chauhan, K.R. 2008. Harmonia Axyridis Adults Avoid Catnip and Grapefruit-derived Terpenoids in Laboratory Bioassays. Bulletin of Insectology. 61(1):81-90. Interpretive Summary: The multicolored Asian lady beetle (MALB) has received considerable attention in recent years for its usefulness as a natural enemy of aphids in various crops during the spring and summer. Unfortunately, it is also known for its annoying behavior of invading houses, during the fall and winter seasons, and forming in groups in attics and other secluded places. Compounds from catnip oil were found to repel MALB adults in the laboratory. This could eventually lead to a sustainable repellent that would help us prevent the MALB from invading the home.
Technical Abstract: We observed the avoidance behavior of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), when adults were exposed to volatiles derived from catnip oil and grapefruit seed. In replicated laboratory bioassays, beetles avoided contact with volatiles emanating from 1 x 9 cm filter paper strips by trying to fly away, jumping back, stopping at, or turning away from the edge of strips. Although avoidance behaviors were found to vary depending on chemical concentration, turning away from the treated edge was predominant. Concentration had a highly significant effect on movement of females or both males and females when challenged with a 50 'g/'l concentration of Z,E-dihydronepetalactone (1ZE-DH) or E,Z-dihydronepetalactone (3EZ-DH), respectively. On average, 95% or 82 - 89% of adults avoided strips treated with this concentration of 1ZE-DH or 3EZ-DH, respectively. Other test compounds, E,Z-iridomyrmecin (2EZ-IRI, 72-79% avoidance) and Z,E-iridomyrmecin (4ZE-IRI, 70-89% avoidance) were less effective. Finally, nootkatone (5NOOTKA, 55% avoidance) and tetrahydronootkatone (6THNOOT, 45-55% avoidance) were least effective. A follow-up experiment using dihydronepetalactone-treated strips, which had been “aged” for 24 hr, indicated that males and females avoided 50 'g/'l of 3EZ-DH rather than the control and more beetles responded to volatiles by turning away. Despite the apparent residual activity of 50 'g/'l of 3EZ-DH, an average of only 55 and 35% of males and females, respectively, avoided the strip edge. Knowledge of the behavior of H. axyridis adults as they approach treated surfaces may provide clues to pushing them away from man-made structures (e. g., houses) with repellents and then pulling them into traps or collecting vessels with attractants.