Mini-review: Aspects of cuticle formation and structure advanced by studies in Nilaparvatalugens

A hallmark of insects is their cuticle that protects them against predators and parasites, prevents desiccation and xenobiotic penetration and, finally, serves locomotion as an exoskeleton. In the last two decades, tremendous efforts have yielded a plethora of molecular and histological data that have boosted our understanding of the mechanisms of cuticle formation and function. As the factors involved in cuticle formation and function are to a large extent specific to insects, these data may be used in intelligent pest management strategies. The brown planthopper Nilaparvata lugens is a major rice pest in Asia. Cuticle research in this species has been following findings in other insect species recapitulating most collected results. There are, in addition, several important data in N. lugens that advanced our understanding in cuticle biology in insects generally. For instance, it was demonstrated in the brown planthopper that a chitin-binding protein, namely NlugCpr47 is needed for organ shaping. Moreover, based on genetic data, it was hypothesised that cuticular lipids may be organised in layers depending on the size of the molecules. Finally, pore canals, the nanotubes system that is used as a transport route for cuticle lipid deposition, were visualised in 3D with high resolution for the first time in an insect. These examples, reviewed in this article, underline the importance of a detailed molecular and histological approach in non-model insects for a better understanding of cuticle biology in general.