Antennal morphology and sexual dimorphism of the ash weevil, Myllocerus subfasciatus Guerin (Coleoptera: Curculionidae)

Abstract

Ash weevil, Myllocerus subfasciatus Guerin (Coleoptera: Curculionidae) is emerging as a major pest on brinjal. Scanning electron microscopic studies of antennal morphology and sexual dimorphism of the ash weevil, M. subfasciatus were carried out. The size, length of body, width of body, thorax, antenna abdomen of females was significantly larger than males (P<0.0001). The weight of females (20-70 mg) is double the weight of males (10-14 mg). The thoracic glands of males have openings on the top whereas the females are lacking such openings. We observed clear difference in the cuticular secretions structures on the male and female abdominal sternites. No difference observed in the cuticular scales, abdominal openings in the last sternites. The reproductive organs and antennal morphology of the male and female ash weevils are described.