Expanding the sensory horizon: chemosensory receptors beyond traditional olfactory and taste organs in insects.

Chemosensation is crucial for insects, governing essential behaviors like foraging, mating, predator avoidance, and habitat selection. Traditionally, research has focused on chemosensory receptors-specifically odorant receptors and gustatory receptors-within primary chemosensory organs such as the antennae and mouthparts. However, recent discoveries reveal that these receptors are also expressed in various non-traditional tissues, including the gut, labial palps, legs, ovipositors, and brain. Beyond classical olfaction and taste, chemosensory receptors are proposed to play key roles in food quality evaluation, internal nutrient sensing and food intake regulation, hormone signaling, metabolic coordination, neuronal circuit development, fertilization, regulation of reproduction, or thermosensation, reflecting their remarkable functional versatility and evolutionary adaptability. In this review, we synthesize the latest research on the expression of chemosensory receptors beyond traditional chemosensory organs, explore their proposed roles in different tissues and projection patterns, and assess their potential as vital targets for advanced pest management techniques.