The ecology of nutrient sensation and perception in insects

A substantial body of evidence suggests that the environment and their metabolic state influence the perception of nutrients by insects.Insects can provide insights into the basic mechanisms of sensory processing and nutrient signaling, which may have broader implications for understanding how other organisms, including humans, perceive and respond to their environment. In addition, by understanding how insects perceive and respond to different nutrients, researchers can develop more effective strategies to control pest populations and improve crop yields.Most studies are limited to few model species, such as Drosophila, thus preventing a broader and universally applicable view on the topic.We develop a perceptional hierarchy hypothesis which suggests that the perception of food by insects is oriented towards nutrients that are particularly beneficial or detrimental. The hypothesis integrates neurobiological, physiological, and ecological aspects of insect nutrient perception. Insects are equipped with neurological, physiological, and behavioral tools to locate potential food sources and assess their nutritional quality based on volatile and chemotactile cues. We summarize current knowledge on insect taste perception and the different modalities of reception and perception. We suggest that the neurophysiological mechanisms of reception and perception are closely linked to the species-specific ecology of different insects. Understanding these links consequently requires a multidisciplinary approach. We also highlight existing knowledge gaps, especially in terms of the exact ligands of receptors, and provide evidence for a perceptional hierarchy suggesting that insects have adapted their reception and perception to preferentially perceive nutrient stimuli that are important for their fitness.