Mating behavior ofXylotrechus pyrrhoderus Bates (Coleoptera: Cerambycidae) V. Female mounting behavior

Female mounting behavior was observed in the grape borerXylotrechus pyrrhoderus Bates (Coleoptera: Cerambycidae) under laboratory conditions. This behavior was directed towards either females (i.e., female homosexual mounting) or males. The female homosexual mounting was strongly elicited in females which had previously been allowed to fly. The frequency of this behavior was not related to the experience of mating. The investigation of the daily temporal pattern in female homosexual mounting activity indicated that the behavior most frequently occurred between 12∶00 and 16∶00, i.e., when females were searching for the pheromone-releasing males. Oviposition was also observed during this time interval. A detailed analysis revealed female mounting behaviors which are characteristic of male mounting behaviors, such as chasing conspecifics and synchronism of licking and abdominal bending. On the other hand, the frequency of male homosexual mounting was lower than that of females. Taken together with cases of other species previously reported, the expression of mounting behavior in females may be related to the evolution of the reproductive system, in which females approach their mates.