Fine Structure and Distribution of Antennal Sensilla of Longicorn BeetlesLeptura arcuataandLeptura aethiops(Coleoptera: Cerambycidae)

The longicorn beetles Leptura arcuata Panzer and Leptura aethiops Poda (Coleoptera: Cerambycidae) are predominant pollination beetles in Eurasia and North America. To further elucidate the mechanism of mate and host location, the type, number, and distribution of antennal sensilla of both species of the longicorn beetles were studied using scanning electron microscopy. The filiform antennae of both sexes of the both species consist of the scape, pedicel, and nine flagellomeres. Based on their morphology, three types of sensilla chaetica, one type of sensilla trichodea, four types of sensilla basiconica, and Böhm bristles were distinguished on the antennae in both sexes. No significant sexual differences in the types, numbers, and distribution of the antennal sensilla were found on the antennae, except for the number of sensilla basiconica type 2. The average number of sensilla basiconica type 2 on the antennae of the males was significant greater than that on the antennae of the females. Based on the ultrastructure we postulated that this type of sensillum on the male beetle's antennae should be responsible for the reception of the sex pheromone produced by the female beetle. The putative functions of other sensillar types also are discussed with reference to their morphology, distribution, and ultrastructure.