Function of aggregation pheromone in the larger grain borer Prostephanus truncatus:: Variation in response to individuals as evidence for a role in sexual selection

The ability of both male and female Prostephanus truncatus beetles to distinguish between the aggregation pheromone signals of two closely located conspecific male beetles was investigated by using an olfactometer. Beetles detected variation between male signalers and visited some signalers more than others. Beetles of both sexes were found to make the same choices. These patterns of preference were found to be mirrored in trap catches of dispersing beetles when single males were used to bait flight traps that were placed in pairs in a woodland habitat in Ghana. The results are discussed with reference to the hypothesis that males signal primarily to attract mates and, therefore, features of the aggregation-pheromone signal may be sexually selected. The implications of the results for current and possible Future pest-management tools are also explored.