ABSTRACT
This research investigates how fourth-instar larvae of the potato tuber moth, Phthorimaea operculella, respond to plant secondary metabolites (sucrose, glucose, nicotine, and tannic acid) both in terms of gustatory electrophysiology and feeding behavior. The objective is to establish a theoretical foundation for employing plant-derived compounds in potato tuber moth control. We employed single-sensillum recording techniques and dual-choice leaf disk assays to assess the gustatory electrophysiological responses and feeding preferences of these larvae towards the mentioned compounds. Sensory neurons responsive to sucrose, glucose, nicotine, and tannic acid were identified in the larvae's medial and lateral sensilla styloconica. Neuronal activity was influenced by stimulus type and concentration. Notably, the two types of sensilla styloconica displayed distinct response patterns for sucrose and glucose while they had similar firing patterns towards nicotine and tannic acid. Sucrose and glucose significantly promoted larval feeding, while nicotine and tannic acid had significant inhibitory effects. These findings demonstrate that the medial and lateral sensilla styloconica house sensory neurons sensitive to both feeding stimulants and inhibitors, albeit with differing response profiles and sensitivities. This study suggests that sucrose and glucose are promising candidates for feeding stimulants, while nicotine and tannic acid show potential as effective feeding inhibitors of P. operculella larvae.
ABSTRACT
Single sensillum recording is an insect extracellular electrophysiological technique, which can measure the electrophysiological responses of a single sensillum to stimuli in insects. It can help explore the electrophysiologi-cal response mechanism of insect olfactory and taste receptors to different semiochemicals. Combined with other techniques, it can be used to understand the molecular genetic mechanisms of olfactory responses, as well as to develop behavior regulators and volatile organic compound biosensors. In this review, we proposed the basic structure and the principle of single sensillum recording, and summarized its applications in insect studies, aiming to provide the foundation for understanding the mechanisms and applications in insect perception of semiochemicals.
