Brochosomes as an antireflective camouflage coating for leafhoppers.

In nature, insects face immense predation pressure, where visual cues play a vital role in predators locating them. To counter this threat, insects employ a variety of nano- and microstructures on their cuticular layer to manipulate and interact with light, enhancing antireflective properties and providing camouflage or reducing detectability by predators. Leafhoppers have a unique extracuticular coating called brochosome, yet its antireflective functions and protein composition remain unclear. Our study demonstrates strong antireflective properties of brochosomes, effectively reducing reflectance on the cuticle surface, especially in the ultraviolet spectrum, to improve evasion from visual predators. Furthermore, we identify four novel structural proteins of the brochosome (BSM) for the first time. Inhibiting their synthesis by RNAi alters brochosome morphology, impacting the optical properties of the cuticle surface. Evolutionary origin analysis of BSM suggests that brochosomes likely originated from a process involving duplication-divergence. Our study reveals that leafhoppers employ a unique camouflage strategy by secreting brochosomes as antireflection nanocoatings, enabling them to evade natural predators and contributing to their evolutionary success.