Taste receptor cells of gypsy moth larvae exhibit varying sensitivities to various phytochemicals

Abstract

Gypsy moth larvae, Lymantria dispar (L.), are highly polyphagous feeders. They possess taste sensory organs, the medial and lateral galeal styloconic sensilla, which play an important role in host-plant selection through the detection of phytochemicals, such as alkaloids. The styloconic sensilla each house four taste receptor cells, including a sugar, salt, deterrent, and inositol cell. Using a single cell electrophysiological tip-recording method, our aim was to characterize the temporal firing patterns and sensitivities of the receptor cells within each sensillum when exposed to a selected phytochemicals. Our results revealed that these cells responded to alkaloids, (i.e., strychnine, aristolochic acid, nicotine, and caffeine), sugars and sugar alcohols, (i.e., sucrose and inositol), and salt (i.e., potassium chloride). The deterrent cell exhibited a robust temporal firing pattern and displayed varying sensitivity to alkaloid stimulation. We are also examining the effects of mixture interactions on food palatability to address that foods contain both positive and negative factors which stimulate or deter feeding, respectively. This study offers insights into the role of phytochemicals, especially alkaloids, in the taste physiology of this larval insect. This study was supported by NIH grants (1R15DC007609-01 and 3R15DC0076409-0151) to V.D.S.