Christine A. Bahlai, cbahlai@uoguelph.ca1, J. Andrew Welsman, jwelsman@uoguelph.ca1, Emily C. Macleod, emacleod@uoguelph.ca1, Arthur W. Schaafsma, aschaafs@ridgetownc.uoguelph.ca2, and Mark K. Sears, msears@uoguelph.ca1. (1) University of Guelph, Department of Environmental Biology, Department of Environmental Biology, University of Guelph, Guelph, ON, Canada, (2) University of Guelph, Department of Plant Agriculture, Ridgetown College, 120 Main St E, Ridgetown, ON, Canada
Harmonia axyridis Pallas is an introduced lady beetle common in eastern North American agroecosystems. Two-choice behavior bioassays were performed to determine if visual and olfactory stimuli from prey hosts and habitats could elicit taxis in wild-collected H. axyridis adults, and if beetles would exhibit a preference between stimuli. Olfactory bioassays were performed in a Y-tube olfactometer and tested response of beetles to the odour of buckthorn (Rhamnus cathartica L.) leaves, apple (Malus domestica Borkh.) leaves, and buckthorn leaves infested with Aphis glycines Matsumura. Visual bioassays were performed in a 1.2m acrylic tube arena, and tested beetle response to simulated treelines, shapes, and apple and buckhorn leaves. Significantly more beetles moved toward the odour of buckthorn leaves than blank air, and to apple than buckthorn. No differences were observed between the number of beetles moving towards buckthorn infested with A. glycines and uninfested buckthorn. Beetles also were significantly more likely to choose some shapes over others in visual trials, but no significant preference between apple and buckthorn foliage was observed.
Species 1: Hemiptera Aphididae
Aphis glycines (soybean aphid)
Species 2: Coleoptera Coccinellidae
Harmonia axyridis (multicolored Asian lady beetle)