Mating Behavior of Xylotrechus pyrrhoderus BATES (Coleoptera : Cerambycidae) II. Female Recognition by Male and the Existence of a Female Sex Pheromone

The mating behavior of the grape borer Xylotrechus pyrrhoderus is composed of two phases. The first phase is the female's in-flight approach to pheromone-releasing males over a distance of more than one meter; the second phase is the male's walking approach to the female which has alighted nearby. The present study indicated that the approach by males to females was mediated by a female sex pheromone. This suggests that the grape borer possesses two different sex pheromones enabling the sexes to effectively encounter each other. The female pheromone induces males to seek a mate and is the sole stimulus to sex recognition by males. However, subsequent behavior was elicited by other stimuli, i.e., a visual stimulus for an approaching male just prior to his contact with a female, and a tactile stimulus for the mounting and abdominal bending behavior for genital contact.