Reinvestigation of the antennal morphology of the white-backed planthopper Sogatella furcifera (Horváth) (Hemiptera: Delphacidae)

Reinvestigation of the antennal morphology of the white-backed planthopper Sogatella furcifera (Horváth), a major pest of rice in Asia, revealed the presence of sensilla and other structures not reported in previous studies of this species. Scanning electron microscopic examination of antennae of males and females confirmed that the antennae of S. furcifera are similar to those of other recently studied species, consisting of scape, pedicel, and flagellum composed of a basal bulb and an apical segmented arista. In contrast to previous studies that only described four types of sensilla, twelve types of sensilla were observed. The scape and pedicel have dispersed sensilla which contain a Böhm bristle, single dome-shaped campaniform sensilla, several sensilla trichodea I and papillae-like sensilla I. A sensilla basoconicum II, several sensilla basiconica I, single sensillum campaniformium II, sensilla trichodea I, sensilla trichodea II, plaque organs, and papillae-like sensilla II occurred on the pedicel. A single sensillum coeloconicum and three sensilla basiconica III are located apically on the posterior surface of the bulb. Sensilla trichodea I were the most abundant and plaque organs were the most conspicuous sensilla, distributed on the pedicel. No differences were observed in antenna shape and basic structure in the males and females. The possible functions of the sensilla are discussed in relation to their morphology and compared to those found in other Fulgoroidea, especially Delphacidae. The external morphology, distribution, and abundance of sensilla located on the antennae of S. furcifera are illustrated, with a brief discussion of their taxonomic, phylogenetic, and putative functional significance.