Gustatory and olfactory responses of Cylindrocopturus adspersus (LeConte) to various plant species in the laboratory

Feeding preferences and olfactory responses of Cylindrocopturus adspersus (LeConte) (Coleoptera:Curculionidae) to nine plant species were compared with sunflower, Helianthus annuus L. (Asteraceae), for stem weevil feeding preference in the laboratory. Sunflower was strongly preferred in each assay. Six crop species were also assayed for stem weevil preference in the absence of sunflower. Although overall feeding was diminished, C. adspersus showed a measurable feeding response to several plant species unrelated to its host plant. In olfactory assays, stem weevils preferred sunflower leaf discs to blank controls, but showed no preference for sunflower stems to blank controls. However, when assayed together, sunflower stems elicited a greater olfactory response than did sunflower leaf discs. Possible explanations regarding the gustatory and olfactory responses of C. adspersus are discussed, as is the potential for employing phytochemical stimuli as baits for incorporation into a pest monitoring program.