MORPHOLOGICAL-STUDIES ON THE ANTENNAL SENSILLA OF THE CIGARETTE BEETLE, LASIODERMA-SERRICORNE (F) (COLEOPTERA, ANOBIIDAE)

In order to identify the pheromone sensitive antennal sensilla of the male cigarette beetle, distribution and frequency of sensilla on the antennal flagellum of both sexes were investigated by scanning electron microscopy. On the flagellar segments, Sensillum basiconicum, S. styloconicum, S. capitulum, and three types of bristles were found. Among these types of sensilla, S. basiconicum and S. styloconicum have structural features indicating them to be olfactory sensilla. S. basiconicum is abundant on the male antenna, three times more so than that on the female antenna. In contrast, no sexual dimorphism was observed in S. styloconicum. Furthermore the number of S. styloconicum is much fewer than S. basiconicum. These findings suggest that S. basiconicum on the male flagella is responsible for detecting the sex pheromone produced by the female.