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Numerous insects have evolved to possess superhydrophobic surfaces, which are thought to limit bacterial contamination through a self-cleaning action. While investigating the adhesion of Pseudomonas aeruginosa on the wings of a species of cicada (Psaltoda claripennis), we discovered that the wing surfaces were actually deadly to the cells. Electron microscopy showed nanopillars on the surface penetrating the cells, which was confirmed to be lethal through viability experiments. The effect was very fast, with individual bacterial cells killed within approximately 3 min. The bactericidal effect is primarily based on the physical surface structure; significant alteration of chemistry through gold coating of the wing failed to inhibit cell death. The cicada wings were able to maintain a clean surface by continuous cleansing through bactericidal action, rather than repelling bacterial cells. Surfaces that inhibit bacterial contamination via their physical structure represent a novel area of research for the development of antibacterial surfaces. Due to the nature of their environments, many insects have a requirement to minimize their contamination by foreign particles in order to retain functionality.[1, 2] These foreign particles may be dust or dirt, or bacterial cells that may seek to colonize and infect the insect. As such, these insects have evolved various strategies or mechanisms for coping with contamination.[3, 4] Several have evolved to possess superhydrophobic surfaces, particularly on their wings, which not only enable them to remain dry and minimize weight, but also bestow a self-cleaning effect.[5–8] Adhesion of water droplets that contact the surface is so …