Morphological characterization and distribution of antennal sensilla of Spodoptera litura (Lepidoptera: Noctuidae) using scanning electron microscopy

Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is a globally significant agricultural pest, causing severe damage to commercial crop production in China. Chemical odor-based trapping is a major approach for S. litura control, making it essential to understand the antennal sensillum types of the insect to enhance development of effective chemical odor attractants. In the present study, the S. litura antennal sensillum types were examined by low-voltage field emission scanning electron microscope and the morphological descriptions were provided. A total of eight types and three subtypes of S. litura antennal sensillum were identified, including Böhm’s bristles (I and II), sensilla trichodea, sensilla basiconica, sensilla chaetica, sensilla coeloconica, sensilla styloconica, sensilla squamiformia (I and II), and sensilla auricillica (I and II). Among them, Böhm bristle II, sensilla squamiformia II, and sensilla auricillica II are reported for the first time for S. litura. This study provides the morphological information to aid in conducting antennal sensillum electrophysiological tests on S. litura. Research Highlights The types of sensilla of Spodoptera litura were examined, identifying eight types and three subtypes, including Böhm’s bristles (I and II), sensilla trichodea, sensilla basiconica, sensilla chaetica, sensilla coeloconica, sensilla styloconica, sensilla squamiformia (I and II), and sensilla auricillica (I and II). Detailed low-voltage field emission scanning electron microscope images and descriptions were provided for each sensillum type.