Different bioassays for investigating orientation responses of the banana weevil, Cosmopolites sordidus, show additive effects of host plant volatiles and a synthetic male-produced aggregation pheromone

Three different bioassay methods to investigate the orientation behaviour of the banana weevil, Cosmopolites sordidus (Germar) ( Coleoptera: Curculionidae), to host plant volatiles and a synthetic pheromone (cosmolure+) were compared. A locomotion compensator was used to separately record walking tracks in response to three odour sources. The data show that C. sordidus uses odour-conditioned anemotaxis in its orientation to the odour sources tested. Of the two olfactometers tested, a dual port olfactometer using a continuous airflow showed stronger discrimination by C. sordidus to the different odours compared with a double pitfall olfactometer. The results of all three bioassays indicate that C. sordidus responds in an additive way to the combination of fermentation plant volatiles and the synthetic pheromone.