Proboscis sensilla of the black cutworm Agrotis ypsilon (Rottemberg) (Lepidoptera: Noctuidae)

Proboscis sensilla are important for feeding biology in Lepidoptera, and are also valuable characters for species recognition and phylogenetic analysis. However, proboscis has not been satisfactorily explored in many groups in Lepidoptera so far. Here we examined the proboscis sensilla of the black cutworm Agrotis ypsilon (Rottemberg), a cosmopolitan agricultural pest of great economic significance, using scanning electron microscopy. Three types of sensilla were found on the proboscis: sensilla chaetica, sensilla basiconica, and sensilla styloconica. Sensilla chaetica occur only on the external surface of the proboscis and become shorter and more scattered toward the tip. Sensilla basiconica are arranged in longitudinal rows on the external proboscis and one longitudinal row in the inner food canal. Sensilla styloconica are the most characteristic sensilla on the proboscis, consisting of a single sensory cone inserted at the top of a stylus with six or seven longitudinal ribs, and are concentrated on the tip region, and are much longer and more numerous in females than in males. The role of proboscis sensilla in the feeding habit prediction is briefly discussed.