A rapid and accurate method for identifying sexuality of Indarbela obliquifasciata Mell (Lepidoptera, Metarbelidae) adults and pupae

Abstract

The bark-eating caterpillar, Indarbela obliquifasciata Mell has become a major pest of garden plants in Guangzhou, China. However, little is known about the sex identification of either adults or pupae. In this paper, according to a comparative morphological study of 55 adults and their corresponding pupae or puparia, we concluded a rapid and accurate method for identifying its sexuality. The results showed a distinct sexual dimorphism in both adults and pupae. In male adults, the antennae are broadly bipectinate, and the ctenii are long with plumose sensory setae. While in female adults, the antennae are narrowly bipectinate, and the ctenii are short with rare setae. In male pupae, the spines on 8th abdominal segment are distributed in a circle, and segments 4–7 are mobile. While in female pupae, the spines on 8th abdominal segment are partially absent on ventral side, and with a short slit at middle part, and segments 4–6 are mobile. The results of this study are of great significance for the field investigation of the sex ratio of adults and pupae and for the study of female pheromones.