Function of pheromones in mating behavior of the Japanese pine sawyer beetle, Monochamus alternatus Hope

The mating behavior of the Japanese pine sawyer beetle Monochamus alternatus was observed in the laboratory. A volatile pheromone of the male which attracted the female and a contact pheromone on the body surface of the female eliciting copulatory behavior in the male were found. The male also showed a similar copulatory behavior to another male when they encountered. Both sexes thus produced a contact pheromone that elicited copulatory behavior in males. However, when two males and one female of the same age were confined in a container, one of the males preferentially attempted copulation with the female. When a male was placed in a container simultaneously with a male dummy and a female dummy, the male preferentially showed a copulatory behavior to the female dummy. Body surface extracts from both sexes elicited mating behavior from males. The two step functions of the pheromones in the mating behavior of this beetle is discussed.