The role of chemical, visual, and tactile cues in the host selection behavior of Ceutorhynchus cardariae, a potential biological control agent for Lepidium draba

Ceutorhynchus cardariae Korotyaev (Coleoptera, Curculionidae), a leaf petiole gall forming weevil, is a potential biological control agent for the invasive perennial mustard, Lepidium draba L.. Host range testing has been previously conducted with results indicating that C. cardariae is a narrow specialist. However, investigating the roles of chemical, visual, and tactile cues in C. cardariae’s host selection behavior will give further insight and provide supporting data that ensure its environmental safety and to avoid any potential unwarranted non-target effects. To accomplish this, several methodological approaches are being preformed: 1) volatiles of L. draba and several confamilial North American Brassicaceae species are being used in bioassays, 2) Combined GC/EADs (combined gas chromotogarphy electroantennagrams) will be preformed to record the antennal responses of C. cardariae to stored volatiles of plant species, 3) The color and shape of the foliage will be used for visual bioassays, 4) ERGs (electro-retinograms), will be preformed to record the retinal responses of the complex eyes in response to specific color wavelength(s) reflected by the plant species foliage, 5) tactile cues will be investigated, specifically with regard to surface and wax extracts. The results of these proposed approaches will be associated with known host range testing data of C cardariae’s to make predictions about its environmental safety.