Infochemical-mediated preference behavior of the maize weevil, Sitophilus zeamais Motschulsky, when searching for its hosts

Behavioral responses of S. zeamais to odours from pulverized wheat, brown rice, sorghum, buckwheat, peanut and cork were compared in a Y-tube-olfactometerbioassay. Results showed that both sexes responded to host volatiles and males were more sensitive than females. The strongest responses to grains of wheat and brown rice were found, and insects reared on these were dramatically heavier than on other tested materials (grain sorghum, buckwheat, peanut and cork). Multiple-choices tests, in which volatiles from males that were removed from the wheat within different minutes were simultaneously presented in the chamber, were used to study whether males can release aggregation pheromone if not on the grain. The pheromone was released by males within about 13 minutes after removal from the grains. Responses to pheromones produced by males were skewed toward females although both sexes were attracted. Both sexes responded most strongly to the odour source comprising pheromone with host volatiles.