Regulation of feeding behaviors by key sugar and bitter gustatory receptors in Helicoverpa armigera

BACKGROUND: Contact chemoreception plays a crucial role in host-plant recognition and acceptance of herbivorous insects; however, the mechanisms by which peripheral taste inputs regulate insect feeding remain unclear. The aim of this study is to clarify the ecological significance of sugar and bitter gustatory receptors (Grs) in the relationship between Helicoverpa armigera and its hostplants. RESULTS: Blocking the positive input via knocking out Gr10 only leads to an increase in palpating frequency, and decreases in both the feeding time and the amounts of larvae on palatable fruit substrates, thereby prolonging the larval stage. Blocking the positive input via knocking out Gr6 only results in a decreased percentage of the proboscis extension reflex (PER) to sucrose and a reduced sucrose intake of adults, thus weakening their ability to detect nectar and decreasing longevity and fecundity. Blocking the negative inputs via knocking out Gr180 decreases palpating frequency and increases both feeding time and amount on unpalatable leaf substrates, leading to early larval mortality and a loss of aversion in adults to coumarin. CONCLUSION: These results indicate that Gr10 is crucial for larvae and Gr6 for adults in tasting some palatable foods, while Gr180 is important for both larvae and adults in avoiding some unpalatable foods. These findings enhance the understanding of how feeding behavior is controlled by taste neuron input in this polyphagous moth species. © 2025 Society of Chemical Industry.