HOST-FINDING BEHAVIOR OF PROSTEPHANUS-TRUNCATUS (HORN) (COL., BOSTRICHIDAE) - PRIMARY ATTRACTION OR RANDOM ATTACK

Host-finding behaviour of Prostephanus truncatus was evaluated in a fo ur-choice olfactometer for reactions to odours of maize, cassava chips , wheat, cowpea (a non-host plant), and woody plant species in which r eproduction has been observed, and of organisms associated with maize stores. P. truncatus reacted in general to odours from starchy commodi ties and to some of the woody plants. Beetles did not respond to volat iles from cowpea or organisms associated with maize stores, but did re act to the aggregation pheromone produced by single male P. truncatus (secondary attraction). P. truncatus raised on cassava and emigrants f rom maize responded as strongly to maize odours as beetles raised on m aize, whereas P. truncatus trapped with pheromone traps showed reduced or no reactions. Stored commodities seem to elicit short-range arrest ment, but not primary attraction at long range. However, stored produc ts might only be attacked facultatively by P. truncatus, co-evolved pr imary attraction could possibly exist to the native host-plant complex .